Clicking on top left corner does not trigger the 'x' button when a window is maximized on a screen that is not aligned to the top of the entire viewport

When a screen configuration has a non-zero y-offset, clicking on the top left corner in that screen does not close the maximized window in that screen.

Steps to reproduce:
1. Have a multihead setup with two screens of different height side by side, aligned by their bottom edges.
2. Maximize a window on the shorter screen
3. Move mouse to top left corner of the shorter screen
4. Notice that the window control buttons vanish, replaced by the window title at the exact corner.
5. Move your mouse inward a bit, and notice that the window controls reappear.

Repeat steps 2-5 with the taller screen, and notice that at #4, the window controls are still present, and clicking on that corner results in the window closing.

Expected behaviour:
The shorter screen should follow the behaviour of the taller screen.

Specific details of my multihead setup is as follows:
LVDS1 connected primary 1366x768+0+270 (normal left inverted right x axis y axis) 277mm x 156mm
HDMI2 connected 1680x1050+1366+0 (normal left inverted right x axis y axis) 434mm x 270mm

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.1.2+14.04.20140305-0ubuntu1
Uname: Linux 3.13.4-hyper1 x86_64
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
CompizPlugins: [core,composite,opengl,copytex,compiztoolbox,decor,vpswitch,extrawm,text,resize,ring,screenshot,place,commands,put,mousepoll,move,gnomecompat,annotate,blur,clone,widget,regex,imgpng,animation,obs,workarounds,neg,bicubic,resizeinfo,grid,expo,session,wall,showmouse,ezoom,unitymtgrabhandles,fade,scale,scalefilter,showdesktop,scaleaddon,unityshell]
CurrentDesktop: Unity
Date: Tue Mar 11 09:54:48 2014
SourcePackage: unity
UpgradeStatus: Upgraded to trusty on 2014-03-03 (7 days ago)