Help! Annoying issue:

This has been driving me crazy! Whenever I’m drawing in Storyboard Pro, the brush tool keeps randomly turning into the selection tool. This happens whenever I’m drawing fast or hit the undo button, and I can’t replicate the error when I intentionally try to make it happen.

(Not sure if this is related, but I’ll be drawing, the brush will turn into the select tool, and then when I hit undo button it goes back to the brush tool. )

Any help would be appreciated! This error has been SO annoying