* uses another virtual to implement WindowActivated() and draw itself in
disabled look just like in R5
* fixed _ButtonRectFor() off by one errors
* tiny problems remain when clicking on the ScrollBar (it is shifted)
* the _ValueFor() might not be perfect
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@14929 a95241bf-73f2-0310-859d-f6bbb57e9c96