diff --git a/native/Avalonia.Native/src/OSX/AutoFitContentView.mm b/native/Avalonia.Native/src/OSX/AutoFitContentView.mm
index 314c579b76..0fa4540726 100644
--- a/native/Avalonia.Native/src/OSX/AutoFitContentView.mm
+++ b/native/Avalonia.Native/src/OSX/AutoFitContentView.mm
@@ -85,7 +85,7 @@
     _settingSize = true;
     [super setFrameSize:newSize];
 
-    auto window = static_cast<id <AvnWindowProtocol>>([self window]);
+    auto window = (id <AvnWindowProtocol>) [self window];
 
     // TODO get actual titlebar size
 
diff --git a/native/Avalonia.Native/src/OSX/AvnWindow.mm b/native/Avalonia.Native/src/OSX/AvnWindow.mm
index 6ff19ead68..54bfe6e38a 100644
--- a/native/Avalonia.Native/src/OSX/AvnWindow.mm
+++ b/native/Avalonia.Native/src/OSX/AvnWindow.mm
@@ -174,6 +174,11 @@
     [self setBackgroundColor: [NSColor clearColor]];
 
     _isExtended = false;
+
+#ifdef IS_NSPANEL
+    [self setCollectionBehavior:NSWindowCollectionBehaviorCanJoinAllSpaces|NSWindowCollectionBehaviorFullScreenAuxiliary];
+#endif
+
     return self;
 }
 
@@ -194,6 +199,8 @@
     [self backingScaleFactor];
 }
 
+
+
 - (void)windowWillClose:(NSNotification *)notification
 {
     _closed = true;
@@ -212,11 +219,14 @@
     // If the window has a child window being shown as a dialog then don't allow it to become the key window.
     for(NSWindow* uch in [self childWindows])
     {
-        auto ch = static_cast<id <AvnWindowProtocol>>(uch);
-        if(ch == nil)
+        if (![uch conformsToProtocol:@protocol(AvnWindowProtocol)])
+        {
             continue;
-        if (ch.isDialog)
-            return false;
+        }
+
+        id <AvnWindowProtocol> ch = (id <AvnWindowProtocol>) uch;
+
+        return !ch.isDialog;
     }
 
     return true;
@@ -372,6 +382,11 @@
 
         if(cparent != nullptr)
         {
+            if(!cparent->IsShown())
+            {
+                return;
+            }
+
             if(cparent->WindowState() == Maximized)
             {
                 cparent->SetWindowState(Normal);
diff --git a/native/Avalonia.Native/src/OSX/PopupImpl.mm b/native/Avalonia.Native/src/OSX/PopupImpl.mm
index 64a8780158..cf3ecefb3c 100644
--- a/native/Avalonia.Native/src/OSX/PopupImpl.mm
+++ b/native/Avalonia.Native/src/OSX/PopupImpl.mm
@@ -50,11 +50,17 @@ protected:
             return S_OK;
         }
     }
+
 public:
     virtual bool ShouldTakeFocusOnShow() override
     {
         return false;
     }
+
+    virtual HRESULT Show(bool activate, bool isDialog) override
+    {
+        return WindowBaseImpl::Show(activate, true);
+    }
 };
 
 
diff --git a/native/Avalonia.Native/src/OSX/WindowBaseImpl.h b/native/Avalonia.Native/src/OSX/WindowBaseImpl.h
index eff13bcb23..0e482f9f30 100644
--- a/native/Avalonia.Native/src/OSX/WindowBaseImpl.h
+++ b/native/Avalonia.Native/src/OSX/WindowBaseImpl.h
@@ -60,6 +60,8 @@ BEGIN_INTERFACE_MAP()
 
     virtual HRESULT Show(bool activate, bool isDialog) override;
 
+    virtual bool IsShown ();
+
     virtual bool ShouldTakeFocusOnShow();
 
     virtual HRESULT Hide() override;
diff --git a/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm b/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm
index db5eb54e3f..0ab120038b 100644
--- a/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm
+++ b/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm
@@ -30,8 +30,8 @@ WindowBaseImpl::WindowBaseImpl(IAvnWindowBaseEvents *events, IAvnGlContext *gl)
     View = [[AvnView alloc] initWithParent:this];
     StandardContainer = [[AutoFitContentView new] initWithContent:View];
 
-    lastPositionSet.X = 100;
-    lastPositionSet.Y = 100;
+    lastPositionSet.X = -1;
+    lastPositionSet.Y = -1;
     lastSize = NSSize { 100, 100 };
     lastMaxSize = NSSize { CGFLOAT_MAX, CGFLOAT_MAX};
     lastMinSize = NSSize { 0, 0 };
@@ -92,7 +92,11 @@ HRESULT WindowBaseImpl::Show(bool activate, bool isDialog) {
         CreateNSWindow(isDialog);
         InitialiseNSWindow();
 
-        SetPosition(lastPositionSet);
+        if(lastPositionSet.X >= 0 && lastPositionSet.Y >= 0)
+        {
+            SetPosition(lastPositionSet);
+        }
+
         UpdateStyle();
 
         [Window setTitle:_lastTitle];
@@ -112,6 +116,11 @@ HRESULT WindowBaseImpl::Show(bool activate, bool isDialog) {
     }
 }
 
+bool WindowBaseImpl::IsShown ()
+{
+    return _shown;
+}
+
 bool WindowBaseImpl::ShouldTakeFocusOnShow() {
     return true;
 }
@@ -191,9 +200,8 @@ HRESULT WindowBaseImpl::GetClientSize(AvnSize *ret) {
         if (ret == nullptr)
             return E_POINTER;
 
-        auto frame = [View frame];
-        ret->Width = frame.size.width;
-        ret->Height = frame.size.height;
+        ret->Width = lastSize.width;
+        ret->Height = lastSize.height;
 
         return S_OK;
     }
@@ -206,9 +214,11 @@ HRESULT WindowBaseImpl::GetFrameSize(AvnSize *ret) {
         if (ret == nullptr)
             return E_POINTER;
 
-        auto frame = [Window frame];
-        ret->Width = frame.size.width;
-        ret->Height = frame.size.height;
+        if(Window != nullptr){
+            auto frame = [Window frame];
+            ret->Width = frame.size.width;
+            ret->Height = frame.size.height;
+        }
 
         return S_OK;
     }
@@ -370,7 +380,10 @@ HRESULT WindowBaseImpl::SetPosition(AvnPoint point) {
 
     @autoreleasepool {
         lastPositionSet = point;
-        [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(point))];
+
+        if(Window != nullptr) {
+            [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(point))];
+        }
 
         return S_OK;
     }
@@ -559,6 +572,7 @@ void WindowBaseImpl::InitialiseNSWindow() {
         [Window setContentMaxSize:lastMaxSize];
 
         [Window setOpaque:false];
+        [Window center];
 
         if (lastMenu != nullptr) {
             [GetWindowProtocol() applyMenu:lastMenu];
@@ -576,7 +590,7 @@ id <AvnWindowProtocol> WindowBaseImpl::GetWindowProtocol() {
         return nullptr;
     }
 
-    return static_cast<id <AvnWindowProtocol>>(Window);
+    return (id <AvnWindowProtocol>) Window;
 }
 
 extern IAvnWindow* CreateAvnWindow(IAvnWindowEvents*events, IAvnGlContext* gl)
diff --git a/native/Avalonia.Native/src/OSX/WindowImpl.mm b/native/Avalonia.Native/src/OSX/WindowImpl.mm
index 7ab2b2b5fc..5b15b4cdfc 100644
--- a/native/Avalonia.Native/src/OSX/WindowImpl.mm
+++ b/native/Avalonia.Native/src/OSX/WindowImpl.mm
@@ -430,6 +430,9 @@ HRESULT WindowImpl::SetWindowState(AvnWindowState state) {
     START_COM_CALL;
 
     @autoreleasepool {
+        auto currentState = _actualWindowState;
+        _lastWindowState = state;
+
         if (Window == nullptr) {
             return S_OK;
         }
@@ -440,9 +443,6 @@ HRESULT WindowImpl::SetWindowState(AvnWindowState state) {
 
         _inSetWindowState = true;
 
-        auto currentState = _actualWindowState;
-        _lastWindowState = state;
-
         if (currentState == Normal) {
             _preZoomSize = [Window frame];
         }
diff --git a/src/Avalonia.Native/WindowImplBase.cs b/src/Avalonia.Native/WindowImplBase.cs
index 735f11bcd5..94a3a5ed9b 100644
--- a/src/Avalonia.Native/WindowImplBase.cs
+++ b/src/Avalonia.Native/WindowImplBase.cs
@@ -116,8 +116,12 @@ namespace Avalonia.Native
             {
                 if (_native != null)
                 {
-                    var s = _native.FrameSize;
-                    return new Size(s.Width, s.Height);
+                    unsafe
+                    {
+                        var s = new AvnSize { Width = -1, Height = -1 };
+                        _native.GetFrameSize(&s);
+                        return s.Width < 0  && s.Height < 0 ? null : new Size(s.Width, s.Height);
+                    }
                 }
 
                 return default;
diff --git a/src/Avalonia.Native/avn.idl b/src/Avalonia.Native/avn.idl
index d6ef0f8918..a1c73e1f03 100644
--- a/src/Avalonia.Native/avn.idl
+++ b/src/Avalonia.Native/avn.idl
@@ -504,7 +504,7 @@ interface IAvnWindowBase : IUnknown
      HRESULT Close();
      HRESULT Activate();
      HRESULT GetClientSize(AvnSize*ret);
-     HRESULT GetFrameSize(AvnSize*ret);
+     HRESULT GetFrameSize(AvnSize*result);
      HRESULT GetScaling(double*ret);
      HRESULT SetMinMaxSize(AvnSize minSize, AvnSize maxSize);
      HRESULT Resize(double width, double height, AvnPlatformResizeReason reason);