If a root tab window has a barImage and a titleControl set, then a window is opened then closed, the root window's titleControl vanishes.
Oddly, a screen orientation change-then-back makes it reappear.
I was almost ready to submit my paid app.net app to the AppStore when I discovered this on an iPad running iOS6.
My testers have also confirmed the issue on an iPhone.
This issue does not occur if there is no barImage set to each window.
Attached is a full test app (called TestBug) which reproduces the bug.