diff --git a/src/osx/cocoa/button.mm b/src/osx/cocoa/button.mm
index fa8938295d..3e4288ba8e 100644
--- a/src/osx/cocoa/button.mm
+++ b/src/osx/cocoa/button.mm
@@ -95,9 +95,16 @@ public:
     virtual void SetBitmap(const wxBitmap& bitmap)
     {
         // switch bezel style for plain pushbuttons
-        if ( bitmap.IsOk() && [GetNSButton() bezelStyle] == NSRoundedBezelStyle )
-            [GetNSButton() setBezelStyle:NSRegularSquareBezelStyle ];
-
+        if ( bitmap.IsOk() )
+        {
+            if ([GetNSButton() bezelStyle] == NSRoundedBezelStyle)
+                [GetNSButton() setBezelStyle:NSRegularSquareBezelStyle];
+        }
+        else
+        {
+            [GetNSButton() setBezelStyle:NSRoundedBezelStyle];
+        }
+        
         wxWidgetCocoaImpl::SetBitmap(bitmap);
     }
 
diff --git a/src/osx/cocoa/window.mm b/src/osx/cocoa/window.mm
index 76fd98719d..26c705fcdd 100644
--- a/src/osx/cocoa/window.mm
+++ b/src/osx/cocoa/window.mm
@@ -1955,7 +1955,11 @@ void wxWidgetCocoaImpl::SetBitmap( const wxBitmap& bitmap )
 {
     if (  [m_osxView respondsToSelector:@selector(setImage:)] )
     {
-        [m_osxView setImage:bitmap.GetNSImage()];
+        if (bitmap.IsOk())
+            [m_osxView setImage:bitmap.GetNSImage()];
+        else
+            [m_osxView setImage:nil];
+
         [m_osxView setNeedsDisplay:YES];
     }
 }