When drawing the decorator buttons lock the DrawingEngine, enable copying to

the front buffer, draw the bitmap, restore the copy to front buffer state and
unlock. This fixes that the updated button state was not actually copyied to
the front buffer (and therefore visible) when a window was inside an update
(disabling front buffer copying).

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25954 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/DefaultDecorator.cpp

@@ -996,10 +996,7 @@ DefaultDecorator::_DrawClose(BRect rect)
 		fCloseBitmaps[index] = bitmap;
 	}
 
-	if (bitmap == NULL)
-		return;
-
-	fDrawingEngine->DrawBitmap(bitmap, rect.OffsetToCopy(0, 0), rect);
+	_DrawButtonBitmap(bitmap, rect);
 }
 
 
@@ -1050,10 +1047,7 @@ DefaultDecorator::_DrawZoom(BRect rect)
 		fZoomBitmaps[index] = bitmap;
 	}
 
-	if (bitmap == NULL)
-		return;
-
-	fDrawingEngine->DrawBitmap(bitmap, rect.OffsetToCopy(0, 0), rect);
+	_DrawButtonBitmap(bitmap, rect);
 }
 
 // _SetFocus
@@ -1093,6 +1087,22 @@ DefaultDecorator::_SetColors()
 }
 
 
+void
+DefaultDecorator::_DrawButtonBitmap(ServerBitmap *bitmap, BRect rect)
+{
+	if (bitmap == NULL)
+		return;
+
+	if (fDrawingEngine->LockParallelAccess()) {
+		bool copyToFrontEnabled = fDrawingEngine->CopyToFrontEnabled();
+		fDrawingEngine->SetCopyToFrontEnabled(true);
+		fDrawingEngine->DrawBitmap(bitmap, rect.OffsetToCopy(0, 0), rect);
+		fDrawingEngine->SetCopyToFrontEnabled(copyToFrontEnabled);
+		fDrawingEngine->UnlockParallelAccess();
+	}
+}
+
+
 /*!
 	\brief Draws a framed rectangle with a gradient.
 	\param down The rectangle should be drawn recessed or not

src/servers/app/DefaultDecorator.h

@@ -68,6 +68,8 @@ class DefaultDecorator: public Decorator {
 	virtual void				_SetColors();
 
  private:
+ 			void				_DrawButtonBitmap(ServerBitmap *bitmap,
+ 									BRect rect);
 			void				_DrawBlendedRect(DrawingEngine *engine,
 									BRect rect, bool down, bool focus);
 			void				_GetButtonSizeAndOffset(const BRect& tabRect,