It's designed for mobile, so the controls are a bit touch-centric. Things are a little trickier with the mouse, I understand.
Try this: do a quick flick left or right with the mouse (doesn't have to be a full turn), and it will finish the rotation automatically rather than forcing you to drag a piece all the way.
Hi, folks! If you see the sticky blocks bug, please try to give as much information as possible that might indicate what could have caused it. OS and Flash Player version might help. This bug gets reported from time to time, but I haven't been able to reproduce it on my machine yet. Thanks!