My CAB behaves strangely on opening, I can't explain... so here's a link to the APK, then you'll be able to see what I mean.
Here's the sample code I used : http://www.technotalkative.com/contextual-action-bar-cab-android/
I've noticed that it does not happen everytime, but when it happens, it happens once and not twice. I don't know where it comes from...
Edit : I found a software which creates GIF, so here's a GIF of the weird behaviour (refresh to see it once again) :
