I use the new Illustrator CC - German language
1. Doubleclick in to a clipping mask (Schnittmaske)
2. wait..........Doubleclick
3. wait..........Doubleclick
If you does´t wait you can click endless and happens nothing.
The old CS5 was fast, worked better than CC, with a sequece of doubleclicks was easly go inside a clipping mask
if you work with a lot of mask this is really irritating.