whenever I'm working on a scribe, if I want to edit an existing text object, this works fine a few times but then all of a sudden the 'edit text option' becomes unresponsive. I click on it, nothing happens. I have to save my scribe, close VideoScribe and then launch the programme again. This happens whenever I'm working on a scribe for a few minutes. I have no other programmes running at the same time and my notebook has enough memory. Any ideas?