puppet properties panel freezing on hand tool ?

A couple of times lately I have been working in the puppet properties panel, adding pins and sticks etc, when all of a sudden it stops working. For example, I might select the stick tool from the tool bar, but when I move the mouse back over the puppet the pointer changes to the hand tool and all I can do is move the puppet around. No matter which tool that I select, the mouse pointer changes to a hand as soon as it moves over the actual work area. I have to close CA and restart work later, which is a nuisance !  Is this a known problem ?