Fix terminal blank when last pane closes (#2665)

Sources/Workspace.swift

@@ -10067,12 +10067,19 @@ final class Workspace: Identifiable, ObservableObject {
             maybeAutoFocusBrowserAddressBarOnPanelFocus(browserPanel, trigger: trigger)
         }
 
-        if trigger == .terminalFirstResponder,
-           panels[panelId] is TerminalPanel {
-            beginEventDrivenLayoutFollowUp(
-                reason: "workspace.focusPanel.terminal",
-                terminalFocusPanelId: panelId
-            )
+        if let terminalPanel = panels[panelId] as? TerminalPanel {
+            // Always set up a focus follow-up when the terminal is not yet first responder.
+            // The .terminalFirstResponder trigger always needs it (reentrant focus assertion).
+            // The .standard trigger needs it when the surface view isn't ready yet (e.g.
+            // new workspace via Cmd+T where the portal hasn't attached to a window yet).
+            let needsFocusFollowUp = trigger == .terminalFirstResponder
+                || !terminalPanel.hostedView.isSurfaceViewFirstResponder()
+            if needsFocusFollowUp {
+                beginEventDrivenLayoutFollowUp(
+                    reason: "workspace.focusPanel.terminal",
+                    terminalFocusPanelId: panelId
+                )
+            }
         }
     }
 
@@ -11811,7 +11818,23 @@ extension Workspace: BonsplitDelegate {
         if bonsplitController.allPaneIds.contains(pane) {
             normalizePinnedTabs(in: pane)
         }
-        scheduleTerminalGeometryReconcile()
+        // When a pane was auto-closed (e.g. N→1 panes), the SwiftUI split view rebuilds
+        // asynchronously, transiently detaching the surviving terminal surface. The synchronous
+        // ensureFocus from applyTabSelection may succeed on the old layout but the first responder
+        // is lost when SwiftUI tears down the split and recreates a single-pane wrapper. Include
+        // the surviving panel in the layout follow-up so the retry loop re-applies focus once the
+        // view is reattached (#2665).
+        if !isDetaching && !bonsplitController.allPaneIds.contains(pane),
+           let survivingPanelId = focusedPanelId,
+           terminalPanel(for: survivingPanelId) != nil {
+            beginEventDrivenLayoutFollowUp(
+                reason: "workspace.paneCollapse",
+                terminalFocusPanelId: survivingPanelId,
+                includeGeometry: true
+            )
+        } else {
+            scheduleTerminalGeometryReconcile()
+        }
         if !isDetaching {
             scheduleFocusReconcile()
         }
@@ -11931,7 +11954,19 @@ extension Workspace: BonsplitDelegate {
             }
         }
 
-        scheduleTerminalGeometryReconcile()
+        // Same pane-collapse focus fix as didCloseTab (#2665): the SwiftUI split view
+        // rebuild can transiently detach the surviving terminal, losing first responder.
+        if shouldScheduleFocusReconcile,
+           let survivingPanelId = focusedPanelId,
+           terminalPanel(for: survivingPanelId) != nil {
+            beginEventDrivenLayoutFollowUp(
+                reason: "workspace.paneCollapse",
+                terminalFocusPanelId: survivingPanelId,
+                includeGeometry: true
+            )
+        } else {
+            scheduleTerminalGeometryReconcile()
+        }
         if shouldScheduleFocusReconcile {
             scheduleFocusReconcile()
         }