Merge pull request #397 from irisitymichaelgrundberg/fix/detached-session-owns-its-pane-size

fix(terminal): let a detached session's own window own its pane size

src/web/public/app.js

@@ -1332,7 +1332,11 @@ class CodemanApp {
     this._redock(id);
   }
 
-  /** Clear all dashboard-side detached state/timers for a session. */
+  /** Clear all dashboard-side detached state/timers for a session, and take its
+   *  sizing back: the popup owned the pane while it was open, so the dashboard's
+   *  record of it is stale and the session it is showing needs re-measuring.
+   *  ⚠️ Not idempotent — each call re-asserts, so a path that redocks twice for
+   *  one close sends two SIGWINCHs. */
   _redock(id) {
     const t = this._detachWatchTimers.get(id);
     if (t) { clearInterval(t); this._detachWatchTimers.delete(id); }
@@ -1340,6 +1344,21 @@ class CodemanApp {
     this._detachOrphanStrikes.delete(id);
     this.detachedWindows.delete(id);
     this._markDetached(id, false);
+    // While the popup owned this session the dashboard sent no resizes, so
+    // `_lastResizeDims` — one value for the whole window — no longer describes
+    // the PTY, which the popup has been sizing. Clearing it makes the next
+    // sendResize report truthfully, on every redock path rather than only the
+    // active one: `selectSession` reads that answer to decide whether to wait
+    // for the TUI's redraw, and a false "unchanged" makes it fetch the frame
+    // before the redraw lands.
+    this._lastResizeDims = null;
+    // Sizing comes back with the session. `force` buys a guaranteed repaint for
+    // the case where popup and dashboard happened to agree on a size; the server
+    // already resizes on its own comparison against the real pane whenever the
+    // two differ.
+    if (this.sessions.has(id) && id === this.activeSessionId) {
+      this.sendResize(id, { force: true })?.catch?.(() => {});
+    }
   }
 
   /** Defer a channel-driven redock briefly. A popup *reload* emits 'redocked'

src/web/public/terminal-ui.js

@@ -940,7 +940,10 @@ Object.assign(CodemanApp.prototype, {
         // causes Ink to re-render at the new row count, garbling terminal output.
         // Local fit() still runs so xterm knows the viewport size for scrolling.
         const keyboardUp = typeof KeyboardHandler !== 'undefined' && KeyboardHandler.keyboardVisible;
-        if (this.activeSessionId && !keyboardUp) {
+        // Same yield as sendResize: never resize a PTY whose session is showing
+        // in its own window. Dragging the dashboard's border must not reshape it.
+        const detachedElsewhere = !this.isSoloWindow && this.detachedSessions?.has(this.activeSessionId);
+        if (this.activeSessionId && !keyboardUp && !detachedElsewhere) {
           const dims = this.fitAddon.proposeDimensions();
           // Enforce minimum dimensions to prevent layout issues
           const cols = dims ? Math.max(dims.cols, MIN_COLS) : MIN_COLS;
@@ -3848,6 +3851,14 @@ Object.assign(CodemanApp.prototype, {
       return;
     }
 
+    // The pane belongs to the popup showing it, so this window has nothing to
+    // restore. Say so rather than reporting a size that was never sent — the
+    // same button in that window does the job.
+    if (!this.isSoloWindow && this.detachedSessions?.has(this.activeSessionId)) {
+      this.showToast('This session is sized by its own window', 'warning');
+      return;
+    }
+
     const dims = this.getTerminalDimensions();
     if (!dims) {
       this.showToast('Could not determine terminal size', 'error');
@@ -4900,6 +4911,17 @@ Object.assign(CodemanApp.prototype, {
     // Fit terminal to container before reading dimensions — ensures local
     // terminal size matches what we report to the server PTY.
     if (this.fitAddon) this.fitAddon.fit();
+    // One PTY cannot hold two sizes. A detached session is owned by its own
+    // window, and the dashboard's terminal is narrower than that window because
+    // the session rail takes width the popup does not have — so both sizing it
+    // makes the CLI draw frames that fit neither, which garbles the popup. The
+    // dashboard yields; the solo window sizes what it alone displays.
+    // (_maybeRefetchFullHistory already stands aside for the same reason.)
+    // ⚠️ AFTER the fit, never before: the local reflow keeps the dashboard's own
+    // xterm right, and only the SERVER write is the dashboard's to withhold —
+    // the mobile-keyboard guard below draws exactly this line. tab-rail-resize
+    // performs its one settle-time refit through this call and has no fallback.
+    if (!this.isSoloWindow && this.detachedSessions?.has(sessionId)) return false;
     const dims = this.getTerminalDimensions();
     if (!dims) return false;
     // Did the dimensions actually change since the last resize we sent? Callers