feat(windows): UI overhaul -- toolbar, unified log, PM windows, channel counts, output volume

- Voice actions (Join Voice, Share Screen Audio) moved to a ToolStrip toolbar and
  a new Voice menu in the menu bar; removed from the bottom voice panel
- Activity log and chat log collapsed into a single RichTextBox (rtbLog); activity
  events appear in gray, chat messages in default color
- Private messaging reworked: each conversation opens in its own modeless
  PrivateMessageForm instead of sharing the main chat log via a scope dropdown;
  cboScope removed; main compose bar always sends to the current channel
- New "Messages -> New Private Message..." menu item (Ctrl+P) opens a UserPickerDialog
  listing all connected server users (not just the current channel) so you can PM
  anyone on the server
- Channel tree now shows live user counts, e.g. "General (3)" -- counts sourced from
  the existing _users dictionary which already tracks all server users with channel IDs
- Global output volume slider (TrackBar, 0-100, default 80) added to the right panel;
  wired to new vc_set_output_volume C ABI function that applies a master gain multiplier
  in the audio engine playback callback after mixing all streams
- vc_set_output_volume added end-to-end: voicecat.h, audio_engine.h/.cpp,
  client.h/.cpp, voicecat.cpp, NativeMethods.cs, VoiceCatClient.cs
- Documented Windows PowerShell ctest requirement in AGENTS.md and CLAUDE.md:
  MinGW binaries exit 0xc0000139 in Git Bash; always run ctest/.exe via PowerShell

22/22 ctest green (PowerShell); dotnet build 0 warnings.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

clients/windows/VoiceCat.App/Forms/MainForm.Designer.cs

@@ -4,8 +4,11 @@ partial class MainForm
 {
     private System.ComponentModel.IContainer components = null!;
 
-    // Menu bar
+    // Menu bar + toolbar
     private MenuStrip menuStrip = null!;
+    private ToolStrip toolStrip = null!;
+    private ToolStripButton tsbJoinVoice = null!;
+    private ToolStripButton tsbScreenShare = null!;
 
     // Status bar
     private Label lblStatus = null!;
@@ -20,23 +23,20 @@ partial class MainForm
     private Label lblUsers = null!;
     private ListBox lstUsers = null!;
 
-    // Right panel: chat transcript, compose row, activity log
+    // Right panel: unified log, compose row, output volume
     private TableLayoutPanel tblRight = null!;
-    private Label lblChat = null!;
-    private RichTextBox rtbChat = null!;
+    private Label lblLog = null!;
+    private RichTextBox rtbLog = null!;
     private TableLayoutPanel tblCompose = null!;
-    private ComboBox cboScope = null!;
     private TextBox txtCompose = null!;
     private Button btnSend = null!;
-    private Label lblActivity = null!;
-    private ListBox lstActivity = null!;
+    private Label lblOutputVolume = null!;
+    private TrackBar trkOutputVolume = null!;
 
     // Voice control panel (docked Bottom)
     private Panel pnlVoice = null!;
     private FlowLayoutPanel flpVoiceTop = null!;
     private FlowLayoutPanel flpVoiceBottom = null!;
-    private Button btnMicToggle = null!;
-    private Button btnScreenShareToggle = null!;
     private CheckBox chkMute = null!;
     private CheckBox chkDeafen = null!;
     private RadioButton radioVad = null!;
@@ -70,19 +70,16 @@ partial class MainForm
         lblUsers = new Label();
         lstUsers = new ListBox();
         tblRight = new TableLayoutPanel();
-        lblChat = new Label();
-        rtbChat = new RichTextBox();
+        lblLog = new Label();
+        rtbLog = new RichTextBox();
         tblCompose = new TableLayoutPanel();
-        cboScope = new ComboBox();
         txtCompose = new TextBox();
         btnSend = new Button();
-        lblActivity = new Label();
-        lstActivity = new ListBox();
+        lblOutputVolume = new Label();
+        trkOutputVolume = new TrackBar();
         pnlVoice = new Panel();
         flpVoiceTop = new FlowLayoutPanel();
         flpVoiceBottom = new FlowLayoutPanel();
-        btnMicToggle = new Button();
-        btnScreenShareToggle = new Button();
         chkMute = new CheckBox();
         chkDeafen = new CheckBox();
         radioVad = new RadioButton();
@@ -97,6 +94,10 @@ partial class MainForm
         pbLevel = new ProgressBar();
         lblVadThreshold = new Label();
         trkVadThreshold = new TrackBar();
+        menuStrip = new MenuStrip();
+        toolStrip = new ToolStrip();
+        tsbJoinVoice = new ToolStripButton();
+        tsbScreenShare = new ToolStripButton();
 
         // ── Status label ──────────────────────────────────────────────────────
         lblStatus.AccessibleName = "Connection status";
@@ -144,78 +145,72 @@ partial class MainForm
         splitLeft.Panel2.Controls.Add(lstUsers);
         splitLeft.Panel2.Controls.Add(lblUsers);
 
-        // ── Chat transcript ───────────────────────────────────────────────────
-        lblChat.Text = "Chat:";
-        lblChat.AutoSize = true;
-        lblChat.Padding = new Padding(2, 2, 2, 1);
+        // ── Unified log ───────────────────────────────────────────────────────
+        lblLog.Text = "Chat & Activity:";
+        lblLog.AutoSize = true;
+        lblLog.Padding = new Padding(2, 2, 2, 1);
 
-        rtbChat.AccessibleName = "Chat transcript";
-        rtbChat.AccessibleDescription = "History of channel and private messages.";
-        rtbChat.Dock = DockStyle.Fill;
-        rtbChat.ReadOnly = true;
-        rtbChat.ScrollBars = RichTextBoxScrollBars.Vertical;
-        rtbChat.BackColor = SystemColors.Window;
-        rtbChat.TabIndex = 0;
+        rtbLog.AccessibleName = "Chat and activity log";
+        rtbLog.AccessibleDescription = "Combined history of chat messages (normal) and activity events (gray).";
+        rtbLog.Dock = DockStyle.Fill;
+        rtbLog.ReadOnly = true;
+        rtbLog.ScrollBars = RichTextBoxScrollBars.Vertical;
+        rtbLog.BackColor = SystemColors.Window;
+        rtbLog.TabIndex = 0;
 
         // ── Compose row ───────────────────────────────────────────────────────
-        cboScope.AccessibleName = "Send to";
-        cboScope.AccessibleDescription =
-            "Choose Channel to send to everyone, or a specific user for a private message.";
-        cboScope.DropDownStyle = ComboBoxStyle.DropDownList;
-        cboScope.Dock = DockStyle.Fill;
-        cboScope.TabIndex = 1;
-
         txtCompose.AccessibleName = "Message text";
-        txtCompose.AccessibleDescription = "Type your message. Press Enter or click Send to send.";
+        txtCompose.AccessibleDescription = "Type your channel message. Press Enter or click Send to send.";
         txtCompose.Dock = DockStyle.Fill;
-        txtCompose.TabIndex = 2;
+        txtCompose.TabIndex = 1;
 
         btnSend.Text = "&Send";
         btnSend.Dock = DockStyle.Fill;
-        btnSend.TabIndex = 3;
+        btnSend.TabIndex = 2;
 
-        tblCompose.ColumnCount = 3;
+        tblCompose.ColumnCount = 2;
         tblCompose.RowCount = 1;
         tblCompose.Dock = DockStyle.Fill;
-        tblCompose.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 165F));
         tblCompose.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100F));
         tblCompose.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 68F));
         tblCompose.RowStyles.Add(new RowStyle(SizeType.Percent, 100F));
         tblCompose.Padding = new Padding(0, 3, 0, 0);
-        tblCompose.Controls.Add(cboScope, 0, 0);
-        tblCompose.Controls.Add(txtCompose, 1, 0);
-        tblCompose.Controls.Add(btnSend, 2, 0);
+        tblCompose.Controls.Add(txtCompose, 0, 0);
+        tblCompose.Controls.Add(btnSend, 1, 0);
 
-        // ── Activity log ──────────────────────────────────────────────────────
-        lblActivity.Text = "Activity:";
-        lblActivity.AutoSize = true;
-        lblActivity.Padding = new Padding(2, 4, 2, 1);
+        // ── Output volume row ─────────────────────────────────────────────────
+        lblOutputVolume.Text = "Output volume:";
+        lblOutputVolume.AutoSize = true;
+        lblOutputVolume.Padding = new Padding(2, 6, 4, 0);
 
-        lstActivity.AccessibleName = "Activity log";
-        lstActivity.AccessibleDescription =
-            "Record of joins, leaves, talk-state changes, and server messages.";
-        lstActivity.Dock = DockStyle.Fill;
-        lstActivity.HorizontalScrollbar = true;
-        lstActivity.TabIndex = 4;
+        trkOutputVolume.AccessibleName = "Output volume";
+        trkOutputVolume.AccessibleDescription = "Global playback volume for all incoming audio.";
+        trkOutputVolume.Minimum = 0;
+        trkOutputVolume.Maximum = 100;
+        trkOutputVolume.Value = 80;
+        trkOutputVolume.TickFrequency = 10;
+        trkOutputVolume.SmallChange = 1;
+        trkOutputVolume.LargeChange = 10;
+        trkOutputVolume.Dock = DockStyle.Fill;
+        trkOutputVolume.TabIndex = 3;
 
         // ── Right table layout ────────────────────────────────────────────────
         tblRight.ColumnCount = 1;
         tblRight.RowCount = 5;
         tblRight.Dock = DockStyle.Fill;
         tblRight.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100F));
-        tblRight.RowStyles.Add(new RowStyle(SizeType.AutoSize));
-        tblRight.RowStyles.Add(new RowStyle(SizeType.Percent, 100F));
-        tblRight.RowStyles.Add(new RowStyle(SizeType.Absolute, 34F));
-        tblRight.RowStyles.Add(new RowStyle(SizeType.AutoSize));
-        tblRight.RowStyles.Add(new RowStyle(SizeType.Absolute, 120F));
-        tblRight.Controls.Add(lblChat, 0, 0);
-        tblRight.Controls.Add(rtbChat, 0, 1);
+        tblRight.RowStyles.Add(new RowStyle(SizeType.AutoSize));        // row 0: lblLog
+        tblRight.RowStyles.Add(new RowStyle(SizeType.Percent, 100F));   // row 1: rtbLog
+        tblRight.RowStyles.Add(new RowStyle(SizeType.Absolute, 34F));   // row 2: compose
+        tblRight.RowStyles.Add(new RowStyle(SizeType.AutoSize));        // row 3: vol label
+        tblRight.RowStyles.Add(new RowStyle(SizeType.Absolute, 45F));   // row 4: vol slider
+        tblRight.Controls.Add(lblLog, 0, 0);
+        tblRight.Controls.Add(rtbLog, 0, 1);
         tblRight.Controls.Add(tblCompose, 0, 2);
-        tblRight.Controls.Add(lblActivity, 0, 3);
-        tblRight.Controls.Add(lstActivity, 0, 4);
+        tblRight.Controls.Add(lblOutputVolume, 0, 3);
+        tblRight.Controls.Add(trkOutputVolume, 0, 4);
 
         // ── Main split ────────────────────────────────────────────────────────
-        // SplitterDistance set in OnLoad — see MainForm.cs.
         splitMain.Dock = DockStyle.Fill;
         splitMain.Panel1MinSize = 150;
         splitMain.TabIndex = 1;
@@ -223,26 +218,6 @@ partial class MainForm
         splitMain.Panel2.Controls.Add(tblRight);
 
         // ── Voice control panel ───────────────────────────────────────────────
-        // Top row: mic start/stop, mute/deafen, VAD/PTT
-        btnMicToggle.Text = "&Join Voice";
-        btnMicToggle.AutoSize = true;
-        btnMicToggle.Margin = new Padding(0, 2, 6, 0);
-        btnMicToggle.TabIndex = 0;
-
-        // Screen-audio share — independent of mic voice (can share without joining voice and
-        // vice versa). The core's WASAPI loopback path (VOICECAT_HAS_LOOPBACK, always on for
-        // the windows-client preset) captures the default render endpoint; see docs/voice.md
-        // §9. Whole-device loopback inherently re-captures this app's own incoming voice mix —
-        // an accepted self-echo characteristic, not a bug.
-        btnScreenShareToggle.Text = "Share Screen &Audio";
-        btnScreenShareToggle.AccessibleName = "Share screen audio";
-        btnScreenShareToggle.AccessibleDescription =
-            "Start or stop sharing your computer's audio (desktop/system audio) with the channel. " +
-            "Independent of the microphone. Captures everything playing through your default speakers.";
-        btnScreenShareToggle.AutoSize = true;
-        btnScreenShareToggle.Margin = new Padding(0, 2, 12, 0);
-        btnScreenShareToggle.TabIndex = 10;
-
         chkMute.Text = "&Mute mic";
         chkMute.AutoSize = true;
         chkMute.Enabled = false;
@@ -291,8 +266,6 @@ partial class MainForm
         flpVoiceTop.Height = 34;
         flpVoiceTop.AutoSize = false;
         flpVoiceTop.Padding = new Padding(4, 2, 4, 0);
-        flpVoiceTop.Controls.Add(btnMicToggle);
-        flpVoiceTop.Controls.Add(btnScreenShareToggle);
         flpVoiceTop.Controls.Add(chkMute);
         flpVoiceTop.Controls.Add(chkDeafen);
         flpVoiceTop.Controls.Add(lblMode);
@@ -330,12 +303,12 @@ partial class MainForm
         pbLevel.Maximum = 100;
         pbLevel.Margin = new Padding(0, 6, 0, 0);
         pbLevel.Style = ProgressBarStyle.Continuous;
-        pbLevel.TabStop = false; // informational, not actionable
+        pbLevel.TabStop = false;
 
         lblVadThreshold.Text = "Sensitivity:";
         lblVadThreshold.AutoSize = true;
         lblVadThreshold.Margin = new Padding(12, 5, 4, 0);
-        lblVadThreshold.Visible = true; // shown when VAD mode active
+        lblVadThreshold.Visible = true;
 
         trkVadThreshold.AccessibleName = "VAD sensitivity";
         trkVadThreshold.AccessibleDescription =
@@ -343,7 +316,7 @@ partial class MainForm
             "Range 1–100; default 25.";
         trkVadThreshold.Minimum = 1;
         trkVadThreshold.Maximum = 100;
-        trkVadThreshold.Value = 76;       // maps to ~0.024 (≈ default 0.025 threshold)
+        trkVadThreshold.Value = 76;
         trkVadThreshold.TickFrequency = 10;
         trkVadThreshold.SmallChange = 1;
         trkVadThreshold.LargeChange = 10;
@@ -369,8 +342,23 @@ partial class MainForm
         pnlVoice.Controls.Add(flpVoiceBottom);  // Fill — added first
         pnlVoice.Controls.Add(flpVoiceTop);     // Top — added last
 
+        // ── Toolbar ───────────────────────────────────────────────────────────
+        tsbJoinVoice.Text = "Join Voice";
+        tsbJoinVoice.DisplayStyle = ToolStripItemDisplayStyle.Text;
+        tsbJoinVoice.CheckOnClick = false;
+
+        tsbScreenShare.Text = "Share Screen Audio";
+        tsbScreenShare.DisplayStyle = ToolStripItemDisplayStyle.Text;
+        tsbScreenShare.CheckOnClick = false;
+
+        toolStrip.Dock = DockStyle.Top;
+        toolStrip.Items.Add(tsbJoinVoice);
+        toolStrip.Items.Add(new ToolStripSeparator());
+        toolStrip.Items.Add(tsbScreenShare);
+        toolStrip.TabIndex = 1;
+        toolStrip.AccessibleName = "Toolbar";
+
         // ── Menu strip ────────────────────────────────────────────────────────
-        menuStrip = new MenuStrip();
         menuStrip.AccessibleName = "Main menu";
         menuStrip.Dock = DockStyle.Top;
         menuStrip.TabIndex = 0;
@@ -380,12 +368,12 @@ partial class MainForm
         AutoScaleMode = AutoScaleMode.Font;
         ClientSize = new Size(960, 680);
         MinimumSize = new Size(700, 540);
-        KeyPreview = true; // form sees KeyDown/KeyUp before focused control (needed for PTT)
-        // Controls added in reverse docking priority: Fill first, then Bottom, then Top.
-        Controls.Add(splitMain);  // DockStyle.Fill
-        Controls.Add(pnlVoice);   // DockStyle.Bottom
-        Controls.Add(lblStatus);  // DockStyle.Top
-        Controls.Add(menuStrip);  // DockStyle.Top (placed at the very top)
+        KeyPreview = true;
+        Controls.Add(splitMain);   // DockStyle.Fill
+        Controls.Add(pnlVoice);    // DockStyle.Bottom
+        Controls.Add(lblStatus);   // DockStyle.Top
+        Controls.Add(toolStrip);   // DockStyle.Top (above status)
+        Controls.Add(menuStrip);   // DockStyle.Top (topmost)
         StartPosition = FormStartPosition.CenterScreen;
         Text = "VoiceCat";
     }

clients/windows/VoiceCat.App/Forms/MainForm.cs

@@ -4,8 +4,6 @@ namespace VoiceCat.App.Forms;
 
 /// <summary>
 /// Post-auth main window. Owns the VoiceCatClient for its entire lifetime.
-/// Phase E: channel tree, user list, chat. Phase F: voice controls, device pickers, PTT,
-/// per-user tuning.
 /// </summary>
 public partial class MainForm : Form
 {
@@ -28,6 +26,13 @@ public partial class MainForm : Form
     private bool _serverMuted;
     private bool _serverDeafened;
 
+    // Private message windows keyed by the other user's ID
+    private readonly Dictionary<uint, PrivateMessageForm> _pmWindows = [];
+
+    // Voice menu items (kept as fields so we can update their text/state)
+    private ToolStripMenuItem _miJoinVoice = null!;
+    private ToolStripMenuItem _miScreenShare = null!;
+
     public MainForm(VoiceCatClient client, uint selfUserId, string nickname)
     {
         InitializeComponent();
@@ -41,7 +46,6 @@ public partial class MainForm : Form
         _client.LevelChanged += OnLevelChanged;
         _pumpTimer.Tick += (_, _) => _client.PumpEvents();
 
-        // M5: load own permissions and build permission-aware menus.
         _ownPermissions = SafeGetPermissions();
         BuildMenus();
         BuildChannelContextMenu();
@@ -49,6 +53,9 @@ public partial class MainForm : Form
 
         _pumpTimer.Start();
 
+        // Apply initial output volume
+        _client.SetOutputVolume(trkOutputVolume.Value / 100f);
+
         // Channel tree
         tvChannels.DoubleClick += TvChannels_DoubleClick;
         tvChannels.KeyDown += TvChannels_KeyDown;
@@ -59,9 +66,14 @@ public partial class MainForm : Form
         txtCompose.KeyDown += TxtCompose_KeyDown;
         btnSend.Click += (_, _) => SendText();
 
+        // Toolbar voice buttons
+        tsbJoinVoice.Click += BtnMicToggle_Click;
+        tsbScreenShare.Click += BtnScreenShareToggle_Click;
+
+        // Output volume slider
+        trkOutputVolume.Scroll += TrkOutputVolume_Scroll;
+
         // Voice controls
-        btnMicToggle.Click += BtnMicToggle_Click;
-        btnScreenShareToggle.Click += BtnScreenShareToggle_Click;
         chkMute.CheckedChanged += (_, _) => ApplySelfMute();
         chkDeafen.CheckedChanged += (_, _) => ApplySelfMute();
         radioVad.CheckedChanged += RadioVad_CheckedChanged;
@@ -77,7 +89,7 @@ public partial class MainForm : Form
         KeyUp += MainForm_KeyUp;
         Deactivate += (_, _) =>
         {
-            if (_micStreamId != 0) _client.SetPushToTalk(false); // release PTT on focus loss
+            if (_micStreamId != 0) _client.SetPushToTalk(false);
         };
 
         BootstrapFromServer();
@@ -101,7 +113,6 @@ public partial class MainForm : Form
         }
         RefreshChannelTree();
         RefreshUserList();
-        RebuildScopeCombo();
         UpdateStatusLabel();
         AddActivity($"Connected to server as {_nickname}");
     }
@@ -114,7 +125,7 @@ public partial class MainForm : Form
         LoadInputDevices();
     }
 
-    // ── Menu / context menu builders (M5) ─────────────────────────────────────
+    // ── Menu / context menu builders ─────────────────────────────────────────
 
     private PermissionsInfo SafeGetPermissions()
     {
@@ -124,17 +135,40 @@ public partial class MainForm : Form
 
     private void BuildMenus()
     {
-        if (!_ownPermissions.CanAdminAccounts) return;
+        // Voice menu — always visible
+        var voiceMenu = new ToolStripMenuItem("&Voice");
 
-        var adminMenu = new ToolStripMenuItem("&Admin");
-        var miAccounts = new ToolStripMenuItem("&Server accounts...");
-        miAccounts.Click += (_, _) =>
+        _miJoinVoice = new ToolStripMenuItem("&Join Voice");
+        _miJoinVoice.Click += BtnMicToggle_Click;
+        voiceMenu.DropDownItems.Add(_miJoinVoice);
+
+        _miScreenShare = new ToolStripMenuItem("Share Screen &Audio");
+        _miScreenShare.Click += BtnScreenShareToggle_Click;
+        voiceMenu.DropDownItems.Add(_miScreenShare);
+
+        menuStrip.Items.Add(voiceMenu);
+
+        // Messages menu — always visible
+        var messagesMenu = new ToolStripMenuItem("&Messages");
+        var miNewPm = new ToolStripMenuItem("&New Private Message...");
+        miNewPm.ShortcutKeys = Keys.Control | Keys.P;
+        miNewPm.Click += (_, _) => OpenNewPmDialog();
+        messagesMenu.DropDownItems.Add(miNewPm);
+        menuStrip.Items.Add(messagesMenu);
+
+        // Admin menu — only if permitted
+        if (_ownPermissions.CanAdminAccounts)
         {
-            using var dlg = new AccountsDialog(_client);
-            dlg.ShowDialog(this);
-        };
-        adminMenu.DropDownItems.Add(miAccounts);
-        menuStrip.Items.Add(adminMenu);
+            var adminMenu = new ToolStripMenuItem("&Admin");
+            var miAccounts = new ToolStripMenuItem("&Server accounts...");
+            miAccounts.Click += (_, _) =>
+            {
+                using var dlg = new AccountsDialog(_client);
+                dlg.ShowDialog(this);
+            };
+            adminMenu.DropDownItems.Add(miAccounts);
+            menuStrip.Items.Add(adminMenu);
+        }
     }
 
     private void BuildChannelContextMenu()
@@ -154,9 +188,7 @@ public partial class MainForm : Form
             }
 
             if (canCreate)
-            {
                 ctx.Items.Add("&Create channel...", null, (_, _) => CreateChannel());
-            }
 
             if (hasSelection && isAdmin)
             {
@@ -185,18 +217,18 @@ public partial class MainForm : Form
             {
                 ctx.Items.Add(new ToolStripSeparator());
 
+                var miPm = new ToolStripMenuItem("Send &Private Message");
+                miPm.Click += (_, _) => OpenPmWindow(user.Id);
+                ctx.Items.Add(miPm);
+
+                ctx.Items.Add(new ToolStripSeparator());
+
                 if (_ownPermissions.CanMoveUsers || _ownPermissions.IsAdmin)
-                {
                     ctx.Items.Add("&Move to channel...", null, (_, _) => MoveSelectedUser());
-                }
                 if (_ownPermissions.CanKick || _ownPermissions.IsAdmin)
-                {
                     ctx.Items.Add("&Kick...", null, (_, _) => KickSelectedUser());
-                }
                 if (_ownPermissions.CanBan || _ownPermissions.IsAdmin)
-                {
                     ctx.Items.Add("&Ban...", null, (_, _) => BanSelectedUser());
-                }
 
                 ctx.Items.Add(new ToolStripSeparator());
 
@@ -274,7 +306,6 @@ public partial class MainForm : Form
         }
         RefreshChannelTree();
         RefreshUserList();
-        RebuildScopeCombo();
     }
 
     private void HandleUserJoined(VoiceCatEvent ev)
@@ -282,8 +313,8 @@ public partial class MainForm : Form
         var user = new UserInfo(ev.UserId, ev.Text ?? $"User#{ev.UserId}", false, ev.ChannelId,
             false, false, false, false);
         _users[ev.UserId] = user;
+        RefreshChannelTree();
         RefreshUserList();
-        RebuildScopeCombo();
         if (ev.ChannelId == _currentChannelId && ev.UserId != _selfUserId)
             AddActivity($"{user.Nickname} joined the channel");
     }
@@ -294,9 +325,11 @@ public partial class MainForm : Form
         bool wasHere = user.ChannelId == _currentChannelId && ev.UserId != _selfUserId;
         _users.Remove(ev.UserId);
         _talkingUsers.Remove(ev.UserId);
+        RefreshChannelTree();
         RefreshUserList();
-        RebuildScopeCombo();
         if (wasHere) AddActivity($"{user.Nickname} left the channel");
+        if (_pmWindows.TryGetValue(ev.UserId, out var pmWin))
+            pmWin.AppendActivity($"{user.Nickname} disconnected from server");
     }
 
     private void HandleUserUpdated()
@@ -314,7 +347,6 @@ public partial class MainForm : Form
         }
         RefreshChannelTree();
         RefreshUserList();
-        RebuildScopeCombo();
     }
 
     private void HandleJoinResult(VoiceCatEvent ev)
@@ -322,9 +354,6 @@ public partial class MainForm : Form
         if (ev.Result == VcResult.Ok)
         {
             _currentChannelId = ev.ChannelId;
-            // The authoritative UserEvent::UPDATED broadcast also reflects this move, but it
-            // may arrive after this result — patch our own entry now for instant, flicker-free
-            // feedback. The later UPDATED is idempotent (sets the same channel).
             if (_users.TryGetValue(_selfUserId, out var self))
                 _users[_selfUserId] = self with { ChannelId = ev.ChannelId };
             RefreshChannelTree();
@@ -354,16 +383,19 @@ public partial class MainForm : Form
                            .LocalDateTime.ToString("HH:mm")
             : DateTime.Now.ToString("HH:mm");
         string sender = GetNickname(ev.UserId);
-        // For a private message, ev.ChannelId carries target_id (the recipient user_id).
-        // When the server relays our own private message back to us, label it with the
-        // recipient; an incoming private message just shows "(private)".
-        string prefix = ev.TextScope == VcTextScope.Private
-            ? (ev.UserId == _selfUserId ? $"(private to {GetNickname(ev.ChannelId)}) " : "(private) ")
-            : "";
-        rtbChat.AppendText($"[{time}] {prefix}{sender}: {ev.Text ?? ""}\n");
-        rtbChat.ScrollToCaret();
-        if (ev.TextScope == VcTextScope.Private && ev.UserId != _selfUserId)
-            AddActivity($"Private message from {sender}");
+
+        if (ev.TextScope == VcTextScope.Private)
+        {
+            // For our own outgoing PM, ev.ChannelId carries the recipient user ID.
+            uint otherUserId = ev.UserId == _selfUserId ? ev.ChannelId : ev.UserId;
+            var win = GetOrOpenPmWindow(otherUserId);
+            bool isSelf = ev.UserId == _selfUserId;
+            win.AppendMessage(time, isSelf, sender, ev.Text ?? "");
+        }
+        else
+        {
+            AppendChat(time, sender, ev.Text ?? "");
+        }
     }
 
     private void HandleTalkState(VoiceCatEvent ev)
@@ -409,8 +441,12 @@ public partial class MainForm : Form
         _screenStreamId = 0;
         txtCompose.Enabled = false;
         btnSend.Enabled = false;
-        btnMicToggle.Enabled = false;
-        btnScreenShareToggle.Enabled = false;
+        tsbJoinVoice.Enabled = false;
+        tsbScreenShare.Enabled = false;
+        _miJoinVoice.Enabled = false;
+        _miScreenShare.Enabled = false;
+        foreach (var win in _pmWindows.Values.ToList()) win.Close();
+        _pmWindows.Clear();
     }
 
     // ── Level meter ───────────────────────────────────────────────────────────
@@ -438,7 +474,8 @@ public partial class MainForm : Form
             if (!byParent.TryGetValue(parentId, out var kids)) return;
             foreach (var ch in kids.OrderBy(c => c.Name))
             {
-                var label = ch.Name;
+                int count = _users.Values.Count(u => u.ChannelId == ch.Id);
+                var label = $"{ch.Name} ({count})";
                 if (ch.PasswordProtected) label += " [password]";
                 if (ch.Id == _currentChannelId) label += " ►";
                 var node = new TreeNode(label) { Tag = ch.Id };
@@ -479,34 +516,7 @@ public partial class MainForm : Form
             lstUsers.Items.Add(new UserListItem(user.Id, label));
         }
         lstUsers.EndUpdate();
-    }
-
-    private void RebuildScopeCombo()
-    {
-        uint prevTarget = (cboScope.SelectedItem is ScopeItem prev &&
-                           prev.Scope == VcTextScope.Private)
-            ? prev.TargetId : 0u;
-
-        cboScope.Items.Clear();
-        cboScope.Items.Add(new ScopeItem("Channel", VcTextScope.Channel, 0));
-        foreach (var u in _users.Values.OrderBy(u => u.Nickname))
-        {
-            if (u.Id == _selfUserId) continue;
-            cboScope.Items.Add(new ScopeItem($"Private: {u.Nickname}", VcTextScope.Private, u.Id));
-        }
-
-        if (prevTarget != 0)
-        {
-            for (int i = 1; i < cboScope.Items.Count; i++)
-            {
-                if (cboScope.Items[i] is ScopeItem si && si.TargetId == prevTarget)
-                {
-                    cboScope.SelectedIndex = i;
-                    return;
-                }
-            }
-        }
-        if (cboScope.Items.Count > 0) cboScope.SelectedIndex = 0;
+        UpdateStatusLabel();
     }
 
     private void UpdateStatusLabel()
@@ -536,7 +546,6 @@ public partial class MainForm : Form
         cboInputDevice.Items.Clear();
         foreach (var d in devices) cboInputDevice.Items.Add(d);
 
-        // Restore selection or pick default
         if (prevDevice is not null)
         {
             for (int i = 0; i < cboInputDevice.Items.Count; i++)
@@ -548,7 +557,6 @@ public partial class MainForm : Form
                 }
             }
         }
-        // Select default device
         for (int i = 0; i < cboInputDevice.Items.Count; i++)
         {
             if (cboInputDevice.Items[i] is DeviceInfo d && d.IsDefault)
@@ -570,18 +578,11 @@ public partial class MainForm : Form
             if (result == VcResult.Ok)
             {
                 _micStreamId = streamId;
-                // Apply selected device if not default
                 if (cboInputDevice.SelectedItem is DeviceInfo { IsDefault: false } dev)
                     _client.SetInputDevice(streamId, dev.Id);
-                // Apply current mode
                 _client.SetInputMode(CurrentInputMode());
                 if (radioVad.Checked) _client.SetVadThreshold(VadThresholdFromSlider());
-                btnMicToggle.Text = "Leave &Voice";
-                chkMute.Enabled = true;
-                chkDeafen.Enabled = true;
-                radioVad.Enabled = true;
-                radioPtt.Enabled = true;
-                radioAlwaysOn.Enabled = true;
+                SetVoiceJoinedState(true);
                 AddActivity("Joined voice — microphone active");
             }
             else
@@ -591,27 +592,29 @@ public partial class MainForm : Form
         }
         else
         {
-            _client.SetPushToTalk(false); // release PTT if held
+            _client.SetPushToTalk(false);
             _client.StopStream(_micStreamId);
             _micStreamId = 0;
             pbLevel.Value = 0;
-            btnMicToggle.Text = "&Join Voice";
-            chkMute.Enabled = false;
-            chkDeafen.Enabled = false;
-            radioVad.Enabled = false;
-            radioPtt.Enabled = false;
-            radioAlwaysOn.Enabled = false;
+            SetVoiceJoinedState(false);
             AddActivity("Left voice");
         }
     }
 
+    private void SetVoiceJoinedState(bool joined)
+    {
+        tsbJoinVoice.Text = joined ? "Leave Voice" : "Join Voice";
+        _miJoinVoice.Text = joined ? "Leave &Voice" : "&Join Voice";
+        chkMute.Enabled = joined;
+        chkDeafen.Enabled = joined;
+        radioVad.Enabled = joined;
+        radioPtt.Enabled = joined;
+        radioAlwaysOn.Enabled = joined;
+    }
+
     private void ApplySelfMute() =>
         _client.SetSelfMute(chkMute.Checked, chkDeafen.Checked);
 
-    // Screen-audio share — independent of mic voice. The core bypasses VAD/PTT/self-mute/
-    // server-mute for non-MIC kinds (client.cpp on_capture_frame), so no input-mode or mute
-    // state applies here. WASAPI loopback captures the default render endpoint (whole-device,
-    // not process-specific — docs/voice.md §9).
     private void BtnScreenShareToggle_Click(object? sender, EventArgs e)
     {
         if (_screenStreamId == 0)
@@ -620,7 +623,8 @@ public partial class MainForm : Form
             if (result == VcResult.Ok)
             {
                 _screenStreamId = streamId;
-                btnScreenShareToggle.Text = "Stop Screen &Audio";
+                tsbScreenShare.Text = "Stop Screen Audio";
+                _miScreenShare.Text = "Stop Screen &Audio";
                 AddActivity("Started sharing screen audio");
             }
             else
@@ -632,11 +636,15 @@ public partial class MainForm : Form
         {
             _client.StopStream(_screenStreamId);
             _screenStreamId = 0;
-            btnScreenShareToggle.Text = "Share Screen &Audio";
+            tsbScreenShare.Text = "Share Screen Audio";
+            _miScreenShare.Text = "Share Screen &Audio";
             AddActivity("Stopped sharing screen audio");
         }
     }
 
+    private void TrkOutputVolume_Scroll(object? sender, EventArgs e) =>
+        _client.SetOutputVolume(trkOutputVolume.Value / 100f);
+
     private void RadioVad_CheckedChanged(object? sender, EventArgs e)
     {
         if (!radioVad.Checked) return;
@@ -662,7 +670,7 @@ public partial class MainForm : Form
         if (_micStreamId != 0)
         {
             _client.SetInputMode(VcInputMode.PushToTalk);
-            _client.SetPushToTalk(false); // start released
+            _client.SetPushToTalk(false);
         }
     }
 
@@ -682,7 +690,6 @@ public partial class MainForm : Form
             _client.SetVadThreshold(VadThresholdFromSlider());
     }
 
-    // threshold = 0.1 × (1 − (value−1) / 99): slider=1→0.1 (least sensitive), slider=100→0.001
     private float VadThresholdFromSlider() =>
         0.1f * (1f - (trkVadThreshold.Value - 1f) / 99f);
 
@@ -713,7 +720,6 @@ public partial class MainForm : Form
     private void MainForm_KeyDown(object? sender, KeyEventArgs e)
     {
         if (!radioPtt.Checked || e.KeyCode != _pttKey || _micStreamId == 0) return;
-        // Don't intercept PTT key while user is typing in a text control
         if (ActiveControl is TextBox or RichTextBox) return;
         _client.SetPushToTalk(true);
         lblPttKey.Text = $"({_pttKey} ▶)";
@@ -765,6 +771,48 @@ public partial class MainForm : Form
             JoinChannelRequest(channelId);
     }
 
+    // ── Private messaging ─────────────────────────────────────────────────────
+
+    private PrivateMessageForm GetOrOpenPmWindow(uint userId)
+    {
+        if (!_pmWindows.TryGetValue(userId, out var win) || win.IsDisposed)
+        {
+            string nick = GetNickname(userId);
+            win = new PrivateMessageForm(_client, userId, nick, _selfUserId);
+            win.FormClosed += (_, _) => _pmWindows.Remove(userId);
+            _pmWindows[userId] = win;
+            win.Show(this);
+        }
+        else
+        {
+            if (win.WindowState == FormWindowState.Minimized)
+                win.WindowState = FormWindowState.Normal;
+            win.BringToFront();
+        }
+        return win;
+    }
+
+    private void OpenPmWindow(uint userId) => GetOrOpenPmWindow(userId);
+
+    private void OpenNewPmDialog()
+    {
+        var others = _users.Values
+            .Where(u => u.Id != _selfUserId)
+            .OrderBy(u => u.Nickname)
+            .ToList();
+
+        if (others.Count == 0)
+        {
+            MessageBox.Show(this, "No other users are connected to the server.",
+                "New Private Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
+            return;
+        }
+
+        using var dlg = new UserPickerDialog(others);
+        if (dlg.ShowDialog(this) == DialogResult.OK)
+            OpenPmWindow(dlg.SelectedUserId);
+    }
+
     // ── M5: Moderation helpers ────────────────────────────────────────────────
 
     private void UpdateSelfServerMuteState(bool muted, bool deafened)
@@ -796,14 +844,8 @@ public partial class MainForm : Form
         if (channel is null) return;
 
         var editInfo = new ChannelEditInfo(
-            channel.Id,
-            channel.ParentId,
-            channel.Name,
-            channel.Topic,
-            channel.PasswordProtected,
-            null,
-            channel.MaxUsers,
-            0,
+            channel.Id, channel.ParentId, channel.Name, channel.Topic,
+            channel.PasswordProtected, null, channel.MaxUsers, 0,
             new AudioConfigInfo(0, false, 48000, 0, 20, 0, true, 0, false, 10));
 
         using var dlg = new ChannelEditDialog(_channels, editInfo);
@@ -876,7 +918,6 @@ public partial class MainForm : Form
     {
         var user = SelectedUser();
         if (user is null) return;
-        // The C ABI does not expose a user's current permissions, so start unchecked.
         var current = new PermissionsInfo(false, false, false, false, false, false);
         using var dlg = new PermissionsDialog(user.Nickname, current);
         if (dlg.ShowDialog(this) != DialogResult.OK || dlg.Result is null) return;
@@ -908,32 +949,29 @@ public partial class MainForm : Form
     {
         string msg = txtCompose.Text.Trim();
         if (string.IsNullOrEmpty(msg)) return;
-
-        var scope = VcTextScope.Channel;
-        uint targetId = _currentChannelId;
-        if (cboScope.SelectedItem is ScopeItem { Scope: VcTextScope.Private } si)
-        {
-            scope = VcTextScope.Private;
-            targetId = si.TargetId;
-        }
-
-        if (scope == VcTextScope.Channel && _currentChannelId == 0) return;
-
-        _client.SendText(scope, targetId, msg);
+        if (_currentChannelId == 0) return;
+        _client.SendText(VcTextScope.Channel, _currentChannelId, msg);
         txtCompose.Clear();
-        // No optimistic echo: the server relays our own message back to us (it no longer
-        // excludes the sender), so HandleTextMessage renders it through the same path as
-        // every other message. Echoing here too would double it.
     }
 
-    // ── Utility ───────────────────────────────────────────────────────────────
+    // ── Log helpers ───────────────────────────────────────────────────────────
+
+    private void AppendChat(string time, string sender, string text)
+    {
+        rtbLog.AppendText($"[{time}] {sender}: {text}\n");
+        rtbLog.ScrollToCaret();
+    }
 
     private void AddActivity(string text)
     {
-        string entry = $"[{DateTime.Now:HH:mm}] {text}";
-        lstActivity.Items.Add(entry);
-        if (lstActivity.Items.Count > 200) lstActivity.Items.RemoveAt(0);
-        lstActivity.TopIndex = lstActivity.Items.Count - 1;
+        string entry = $"[{DateTime.Now:HH:mm}] {text}\n";
+        int selStart = rtbLog.TextLength;
+        rtbLog.AppendText(entry);
+        rtbLog.Select(selStart, entry.Length);
+        rtbLog.SelectionColor = Color.Gray;
+        rtbLog.Select(rtbLog.TextLength, 0);
+        rtbLog.SelectionColor = rtbLog.ForeColor;
+        rtbLog.ScrollToCaret();
     }
 
     private string GetNickname(uint userId)
@@ -949,9 +987,8 @@ public partial class MainForm : Form
         _pumpTimer.Stop();
         _client.LevelChanged -= OnLevelChanged;
         _client.EventReceived -= OnEvent;
-        // Stop any active local streams before tearing down — the core stops loopback in
-        // stream_stop/destroy, but explicit stops ensure clean StreamStop protocol messages
-        // go out before Disconnect closes the control channel.
+        foreach (var win in _pmWindows.Values.ToList()) win.Close();
+        _pmWindows.Clear();
         if (_screenStreamId != 0) _client.StopStream(_screenStreamId);
         if (_micStreamId != 0) _client.StopStream(_micStreamId);
         _client.Disconnect();
@@ -961,13 +998,6 @@ public partial class MainForm : Form
 
     // ── Private types ─────────────────────────────────────────────────────────
 
-    private sealed class ScopeItem(string display, VcTextScope scope, uint targetId)
-    {
-        public VcTextScope Scope { get; } = scope;
-        public uint TargetId { get; } = targetId;
-        public override string ToString() => display;
-    }
-
     private sealed class UserListItem(uint userId, string display)
     {
         public uint UserId { get; } = userId;

clients/windows/VoiceCat.App/Forms/PrivateMessageForm.cs

@@ -0,0 +1,115 @@
+using VoiceCat.Interop;
+
+namespace VoiceCat.App.Forms;
+
+/// <summary>
+/// Modeless window for a single private message conversation.
+/// Created by MainForm and shown non-modally; MainForm routes incoming PMs here.
+/// </summary>
+public sealed class PrivateMessageForm : Form
+{
+    private readonly VoiceCatClient _client;
+    private readonly uint _userId;
+    private readonly uint _selfUserId;
+
+    private readonly RichTextBox _rtbHistory;
+    private readonly TextBox _txtCompose;
+    private readonly Button _btnSend;
+
+    public PrivateMessageForm(VoiceCatClient client, uint userId, string nickname, uint selfUserId)
+    {
+        _client = client;
+        _userId = userId;
+        _selfUserId = selfUserId;
+
+        Text = $"Private Message — {nickname}";
+        ClientSize = new Size(480, 360);
+        MinimumSize = new Size(320, 240);
+        StartPosition = FormStartPosition.Manual;
+
+        _rtbHistory = new RichTextBox
+        {
+            ReadOnly = true,
+            Dock = DockStyle.Fill,
+            ScrollBars = RichTextBoxScrollBars.Vertical,
+            BackColor = SystemColors.Window,
+            AccessibleName = "Message history",
+        };
+
+        var composePanel = new TableLayoutPanel
+        {
+            Dock = DockStyle.Bottom,
+            Height = 34,
+            ColumnCount = 2,
+            RowCount = 1,
+            Padding = new Padding(0, 3, 0, 0),
+        };
+        composePanel.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100F));
+        composePanel.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 68F));
+        composePanel.RowStyles.Add(new RowStyle(SizeType.Percent, 100F));
+
+        _txtCompose = new TextBox
+        {
+            Dock = DockStyle.Fill,
+            AccessibleName = "Message text",
+        };
+        _btnSend = new Button
+        {
+            Text = "&Send",
+            Dock = DockStyle.Fill,
+        };
+
+        composePanel.Controls.Add(_txtCompose, 0, 0);
+        composePanel.Controls.Add(_btnSend, 1, 0);
+
+        Controls.Add(_rtbHistory);
+        Controls.Add(composePanel);
+
+        _txtCompose.KeyDown += (_, e) =>
+        {
+            if (e.KeyCode == Keys.Enter) { Send(); e.Handled = e.SuppressKeyPress = true; }
+        };
+        _btnSend.Click += (_, _) => Send();
+    }
+
+    // Called by MainForm when a PM message arrives (or we send one and the server echoes it).
+    public void AppendMessage(string time, bool isSelf, string sender, string text)
+    {
+        if (IsDisposed) return;
+        string line = $"[{time}] {sender}: {text}\n";
+        int selStart = _rtbHistory.TextLength;
+        _rtbHistory.AppendText(line);
+        if (isSelf)
+        {
+            _rtbHistory.Select(selStart, line.Length);
+            _rtbHistory.SelectionColor = Color.Gray;
+            _rtbHistory.Select(_rtbHistory.TextLength, 0);
+            _rtbHistory.SelectionColor = _rtbHistory.ForeColor;
+        }
+        _rtbHistory.ScrollToCaret();
+    }
+
+    // Called by MainForm for status events (e.g., the other user disconnected).
+    public void AppendActivity(string text)
+    {
+        if (IsDisposed) return;
+        string line = $"[{DateTime.Now:HH:mm}] {text}\n";
+        int selStart = _rtbHistory.TextLength;
+        _rtbHistory.AppendText(line);
+        _rtbHistory.Select(selStart, line.Length);
+        _rtbHistory.SelectionColor = Color.Gray;
+        _rtbHistory.Select(_rtbHistory.TextLength, 0);
+        _rtbHistory.SelectionColor = _rtbHistory.ForeColor;
+        _rtbHistory.ScrollToCaret();
+    }
+
+    private void Send()
+    {
+        string msg = _txtCompose.Text.Trim();
+        if (string.IsNullOrEmpty(msg)) return;
+        _client.SendText(VcTextScope.Private, _userId, msg);
+        _txtCompose.Clear();
+        // No optimistic echo: the server relays our own message back, so AppendMessage is
+        // called from MainForm.HandleTextMessage when the echo arrives.
+    }
+}

clients/windows/VoiceCat.App/Forms/UserPickerDialog.cs

@@ -0,0 +1,99 @@
+using VoiceCat.Interop;
+
+namespace VoiceCat.App.Forms;
+
+/// <summary>
+/// Simple modal dialog for picking one user from a list of all server users.
+/// Used by "New Private Message" to let the user send a PM to anyone on the server.
+/// </summary>
+public sealed class UserPickerDialog : Form
+{
+    private readonly ListBox _lstUsers;
+    private readonly Button _btnOk;
+    private readonly Button _btnCancel;
+
+    private readonly List<UserInfo> _users;
+
+    public uint SelectedUserId { get; private set; }
+
+    public UserPickerDialog(List<UserInfo> users)
+    {
+        _users = users;
+
+        Text = "New Private Message";
+        ClientSize = new Size(280, 320);
+        MinimumSize = new Size(220, 240);
+        FormBorderStyle = FormBorderStyle.FixedDialog;
+        MaximizeBox = false;
+        MinimizeBox = false;
+        StartPosition = FormStartPosition.CenterParent;
+
+        var lbl = new Label
+        {
+            Text = "Select a user:",
+            AutoSize = true,
+            Padding = new Padding(6, 6, 6, 2),
+            Dock = DockStyle.Top,
+        };
+
+        _lstUsers = new ListBox
+        {
+            Dock = DockStyle.Fill,
+            AccessibleName = "User list",
+        };
+        foreach (var u in users)
+            _lstUsers.Items.Add(new UserItem(u.Id, u.Nickname));
+
+        var btnPanel = new FlowLayoutPanel
+        {
+            Dock = DockStyle.Bottom,
+            FlowDirection = FlowDirection.RightToLeft,
+            Height = 40,
+            Padding = new Padding(4),
+            AutoSize = false,
+        };
+
+        _btnCancel = new Button
+        {
+            Text = "Cancel",
+            DialogResult = DialogResult.Cancel,
+            AutoSize = true,
+        };
+        _btnOk = new Button
+        {
+            Text = "OK",
+            DialogResult = DialogResult.OK,
+            AutoSize = true,
+            Enabled = false,
+        };
+        AcceptButton = _btnOk;
+        CancelButton = _btnCancel;
+
+        btnPanel.Controls.Add(_btnCancel);
+        btnPanel.Controls.Add(_btnOk);
+
+        Controls.Add(_lstUsers);
+        Controls.Add(lbl);
+        Controls.Add(btnPanel);
+
+        _lstUsers.SelectedIndexChanged += (_, _) =>
+            _btnOk.Enabled = _lstUsers.SelectedItem is UserItem;
+        _lstUsers.DoubleClick += (_, _) =>
+        {
+            if (_lstUsers.SelectedItem is UserItem) DialogResult = DialogResult.OK;
+        };
+    }
+
+    protected override void OnFormClosing(FormClosingEventArgs e)
+    {
+        if (DialogResult == DialogResult.OK && _lstUsers.SelectedItem is UserItem item)
+            SelectedUserId = item.UserId;
+        base.OnFormClosing(e);
+    }
+
+    private sealed class UserItem(uint userId, string nickname)
+    {
+        public uint UserId { get; } = userId;
+        public override string ToString() => nickname;
+    }
+}

clients/windows/VoiceCat.Interop/NativeMethods.cs

@@ -77,6 +77,9 @@ internal static partial class NativeMethods
     [LibraryImport(LibName)]
     internal static partial VcResult vc_set_self_mute(nint c, int micMuted, int deafened);
 
+    [LibraryImport(LibName)]
+    internal static partial VcResult vc_set_output_volume(nint c, float gain);
+
     [LibraryImport(LibName)]
     internal static partial VcResult vc_set_remote_stream(nint c, uint userId, uint streamId,
         float gain, int muted, int noiseReduction);

clients/windows/VoiceCat.Interop/VoiceCatClient.cs

@@ -204,6 +204,9 @@ public sealed class VoiceCatClient : IDisposable
     public VcResult SetSelfMute(bool micMuted, bool deafened) =>
         NativeMethods.vc_set_self_mute(_handle.DangerousGetHandle(), micMuted ? 1 : 0, deafened ? 1 : 0);
 
+    public VcResult SetOutputVolume(float gain) =>
+        NativeMethods.vc_set_output_volume(_handle.DangerousGetHandle(), gain < 0f ? 0f : gain);
+
     public VcResult SetRemoteStream(uint userId, uint streamId, float gain, bool muted, bool noiseReduction) =>
         NativeMethods.vc_set_remote_stream(_handle.DangerousGetHandle(), userId, streamId, gain,
             muted ? 1 : 0, noiseReduction ? 1 : 0);