add OnInitialiseNSWindow to allow inheritors to hook into NSWindow/Panel setup before being shown.

native/Avalonia.Native/src/OSX/PopupImpl.mm

@@ -26,13 +26,17 @@ private:
     PopupImpl(IAvnWindowEvents* events, IAvnGlContext* gl) : WindowBaseImpl(events, gl)
     {
         WindowEvents = events;
-        [Window setLevel:NSPopUpMenuWindowLevel];
     }
 protected:
     virtual NSWindowStyleMask GetStyle() override
     {
         return NSWindowStyleMaskBorderless;
     }
+    
+    virtual void OnInitialiseNSWindow () override
+    {
+        [Window setLevel:NSPopUpMenuWindowLevel];
+    }
 
 public:
     virtual bool ShouldTakeFocusOnShow() override
@@ -54,4 +58,4 @@ extern IAvnPopup* CreateAvnPopup(IAvnWindowEvents*events, IAvnGlContext* gl)
         IAvnPopup* ptr = dynamic_cast<IAvnPopup*>(new PopupImpl(events, gl));
         return ptr;
     }
-}
+}

native/Avalonia.Native/src/OSX/WindowBaseImpl.h

@@ -104,6 +104,8 @@ protected:
     virtual NSWindowStyleMask GetStyle();
 
     void UpdateStyle();
+                           
+    virtual void OnInitialiseNSWindow ();
 
 private:
     void CreateNSWindow (bool isDialog);

native/Avalonia.Native/src/OSX/WindowBaseImpl.mm

@@ -567,6 +567,11 @@ void WindowBaseImpl::CreateNSWindow(bool isDialog) {
     }
 }
 
+void WindowBaseImpl::OnInitialiseNSWindow()
+{
+    
+}
+
 void WindowBaseImpl::InitialiseNSWindow() {
     if(Window != nullptr) {
         [Window setContentView:StandardContainer];
@@ -586,6 +591,8 @@ void WindowBaseImpl::InitialiseNSWindow() {
                 [GetWindowProtocol() showWindowMenuWithAppMenu];
             }
         }
+        
+        OnInitialiseNSWindow();
     }
 }
 

native/Avalonia.Native/src/OSX/WindowImpl.h

@@ -88,6 +88,8 @@ BEGIN_INTERFACE_MAP()
     virtual HRESULT SetWindowState (AvnWindowState state) override;
 
     virtual bool IsDialog() override;
+    
+    virtual void OnInitialiseNSWindow() override;
 
 protected:
     virtual NSWindowStyleMask GetStyle() override;

native/Avalonia.Native/src/OSX/WindowImpl.mm

@@ -21,9 +21,6 @@ WindowImpl::WindowImpl(IAvnWindowEvents *events, IAvnGlContext *gl) : WindowBase
     _actualWindowState = Normal;
     _lastTitle = @"";
     WindowEvents = events;
-    [Window disableCursorRects];
-    [Window setTabbingMode:NSWindowTabbingModeDisallowed];
-    [Window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenPrimary];
 }
 
 void WindowImpl::HideOrShowTrafficLights() {
@@ -51,25 +48,29 @@ void WindowImpl::HideOrShowTrafficLights() {
     }
 }
 
+void WindowImpl::OnInitialiseNSWindow(){
+    [GetWindowProtocol() setCanBecomeKeyWindow:true];
+    [Window disableCursorRects];
+    [Window setTabbingMode:NSWindowTabbingModeDisallowed];
+    [Window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenPrimary];
+
+    [Window setTitle:_lastTitle];
+    
+    if(_isClientAreaExtended)
+    {
+        [GetWindowProtocol() setIsExtended:true];
+        SetExtendClientArea(true);
+    }
+}
+
 HRESULT WindowImpl::Show(bool activate, bool isDialog) {
     START_COM_CALL;
 
     @autoreleasepool {
         _isDialog = isDialog;
 
-        bool created = Window == nullptr;
-
         WindowBaseImpl::Show(activate, isDialog);
 
-        if(created)
-        {
-            if(_isClientAreaExtended)
-            {
-                [GetWindowProtocol() setIsExtended:true];
-                SetExtendClientArea(true);
-            }
-        }
-
         HideOrShowTrafficLights();
 
         return SetWindowState(_lastWindowState);