Window controls don't appear when approaching from the left-most column of pixels

Steps to reproduce:
1. open a window and maximize it (e.g. nautilus)
2. move the moese away from the top panel to make the window controls disappear
3. move the mouse to the left edge of the screen and move it slowly upwards until it enters the panel
4. the window controls fail to appear unless you move the mouse 1px to the right or more and only as long as the mouse does *not* touch the top edge of the screen.

If it touches the top edge, then the window controls will not appear unless you move the mouse over the invisible menu area.

This looks like some bug in the hit-testing for the window controls.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: unity 4.10.2-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-9.14-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
NonfreeKernelModules: fglrx
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,move,gnomecompat,imgpng,mousepoll,resize,vpswitch,regex,grid,snap,obs,commands,animation,place,session,expo,unitymtgrabhandles,wall,workarounds,ezoom,staticswitcher,fade,scale,unityshell,scaleaddon]
Date: Sun Aug 28 02:29:35 2011
SourcePackage: unity
UpgradeStatus: Upgraded to oneiric on 2011-08-26 (1 days ago)