fix: stop clicks in the main window from starting a native window drag

CHANGELOG.md

@@ -43,6 +43,7 @@ Programa is a fork of [cmux](https://github.com/manaflow-ai/cmux); for history p
 - The `programa codex install-hooks` and `uninstall-hooks` legacy aliases. Use `programa codex install-integration` and `uninstall-integration`.
 
 ### Fixed
+- Dragging the sidebar edge resizes the sidebar again instead of moving the whole window.
 - The Window menu's Fill, Center, Move & Resize, Full Screen Tile and Move to Display items, and their shortcuts, work again. The main window had been marked not movable, which makes macOS disable all of them.
 - The notifications popover now opens in minimal mode, the default layout. Show Notifications (⌘I), the sidebar bell and the menu bar icon's Show Notifications did nothing there.
 - Port chips in the sidebar now show up again for terminals restored after relaunching Programa. The restored terminals kept their running shell, but port scanning never learned about them.

Sources/WindowSwizzles.swift

@@ -165,8 +165,14 @@ extension NSWindow {
             return
         }
 
-        guard shouldSuppressWindowMoveForFolderDrag(window: self, event: event),
-              let contentView = self.contentView else {
+        // The window stays isMovable so AppKit validates the Window menu tiling
+        // items, but no click may start a native window drag: one on the SwiftUI
+        // sidebar resizer band moved the window instead of resizing the sidebar,
+        // and folder-icon drags dragged the window along. Every deliberate drag
+        // surface (WindowDragHandleView, the titlebar background above) re-enables
+        // movability around its own performDrag via withTemporaryWindowMovableEnabled.
+        guard event.type == .leftMouseDown, isMovable,
+              contentView is MainWindowHostingViewMarker else {
 #if DEBUG
             if event.type == .keyDown {
                 folderGuardMs = (ProcessInfo.processInfo.systemUptime - folderGuardStart) * 1000.0
@@ -179,39 +185,10 @@ extension NSWindow {
             programa_sendEvent(event)
             return
         }
-#if DEBUG
-        if event.type == .keyDown {
-            folderGuardMs = (ProcessInfo.processInfo.systemUptime - folderGuardStart) * 1000.0
-        }
-        let originalDispatchStart = event.type == .keyDown ? ProcessInfo.processInfo.systemUptime : 0
-#endif
-
-        let contentPoint = contentView.convert(event.locationInWindow, from: nil)
-        let hitView = contentView.hitTest(contentPoint)
-        let previousMovableState = isMovable
-        if previousMovableState {
-            isMovable = false
-        }
-
-        #if DEBUG
-        let hitDesc = hitView.map { String(describing: type(of: $0)) } ?? "nil"
-        dlog("window.sendEvent.folderDown suppress=1 hit=\(hitDesc) wasMovable=\(previousMovableState)")
-        #endif
 
+        isMovable = false
         programa_sendEvent(event)
-#if DEBUG
-        if event.type == .keyDown {
-            originalDispatchMs = (ProcessInfo.processInfo.systemUptime - originalDispatchStart) * 1000.0
-        }
-#endif
-
-        if previousMovableState {
-            isMovable = previousMovableState
-        }
-
-        #if DEBUG
-        dlog("window.sendEvent.folderDown restore nowMovable=\(isMovable)")
-        #endif
+        isMovable = true
     }
 
     @objc func programa_performKeyEquivalent(with event: NSEvent) -> Bool {

programaTests/WindowAndDragTests.swift

@@ -1571,33 +1571,51 @@ final class WindowMoveSuppressionHitPathTests: XCTestCase {
         }
     }
 
-    private func movabilityDuringMouseDown(contentView: NSView) -> (during: Bool?, after: Bool) {
+    private struct MovabilityRecordingRepresentable: NSViewRepresentable {
+        let view: MovabilityRecordingView
+        func makeNSView(context: Context) -> MovabilityRecordingView { view }
+        func updateNSView(_ nsView: MovabilityRecordingView, context: Context) {}
+    }
+
+    /// The click only reaches the recorder once the window is on screen and key;
+    /// an unshown window drops it before hit-testing.
+    private func movabilityDuringMouseDown(
+        contentView: (MovabilityRecordingView) -> NSView
+    ) -> (during: Bool?, after: Bool) {
         let window = NSWindow(
             contentRect: NSRect(x: 0, y: 0, width: 320, height: 180),
             styleMask: [.titled, .closable],
             backing: .buffered,
             defer: false
         )
         defer { window.orderOut(nil) }
-        window.contentView = contentView
+        let recorder = MovabilityRecordingView(frame: NSRect(x: 0, y: 0, width: 320, height: 180))
+        window.contentView = contentView(recorder)
         window.isMovable = true
-        let view = MovabilityRecordingView(frame: NSRect(x: 0, y: 0, width: 80, height: 60))
-        contentView.addSubview(view)
-        window.sendEvent(makeMouseEvent(type: .leftMouseDown, location: NSPoint(x: 40, y: 30), window: window))
-        return (view.movableDuringMouseDown, window.isMovable)
+        window.makeKeyAndOrderFront(nil)
+        window.displayIfNeeded()
+        window.contentView?.layoutSubtreeIfNeeded()
+        window.sendEvent(makeMouseEvent(type: .leftMouseDown, location: NSPoint(x: 160, y: 90), window: window))
+        return (recorder.movableDuringMouseDown, window.isMovable)
     }
 
     /// A movable main window must not let a plain click start a native window drag:
     /// the sidebar resizer band moved the window instead of resizing the sidebar.
     func testMainWindowMouseDownDispatchKeepsWindowImmovableThenRestoresMovable() {
-        let result = movabilityDuringMouseDown(contentView: MainWindowHostingView(rootView: EmptyView()))
+        let result = movabilityDuringMouseDown { recorder in
+            MainWindowHostingView(rootView: MovabilityRecordingRepresentable(view: recorder))
+        }
         XCTAssertEqual(result.during, false)
         XCTAssertTrue(result.after)
     }
 
     /// Other windows (Settings, Debug windows) keep native window dragging.
     func testNonMainWindowMouseDownDispatchLeavesWindowMovable() {
-        let result = movabilityDuringMouseDown(contentView: NSView())
+        let result = movabilityDuringMouseDown { recorder in
+            let container = NSView(frame: recorder.frame)
+            container.addSubview(recorder)
+            return container
+        }
         XCTAssertEqual(result.during, true)
         XCTAssertTrue(result.after)
     }