tool changing problem on toonboom studio

Im a new user for toon boom studio and i have been enjoying the program alot, but for a while now some of my animations my cursor has been changing to a grabber icon and not allowing me to continue drawing no matter what icon i press. Would any one be able to tell me what is wrong? and how i can stop this from happening?

I have heard about this problem, however I am unable to reproduce it.

Are you using Mac, if so which version?

I am using a pc, I notice though that this problem usually happens when ever i minimize my project to go on the internet or something like that. Is there a way that i can get out of it because most of the responses ive recieved said it was my Wacom tablet, and others say i just have to select a cell and start drawing.