I'm using AC v6.3 and I just encountered a strange behaviour of the title buttons:
1. Create a new project, place SkinManager and SkinProvider on the form 2. Run the project 3. Click on the form, move the form and hoover over the close button
Now the Close Button Hoover Picture is painted at the top left corner of the display
4. If you don't see the effect, repeat the click, move and hoover actions a few times