Operating system: OS X 10.9.5
Graphics card: NVIDIA GeForce GT 650M 1024 MB
Broken: I have seen it since 2.69.0 to 2.72a (haven't tested it on any version prior 2.69.0)
Short description of error
On OS X, when switching from another app to Blender via Mission Control (the OS X feature that spreads out in your screen every window/app you have open) it doesn't switch. Blender kind of hides in the back, you need to repeat the process and then it works fine. Here is a dropbox link to a quick video for easier understanding, sorry if I can't explain myself with words:
Exact steps for others to reproduce the error
With Blender opened, switch to another app, then via Mission Control select Blender. It will hide itself.