Comment 6 for bug 890589

I recently ran into this issue again, and after a bit of experimenting I noticed something: It only happens (sometimes) when I run Pinta through the MonoDevelop debug command. This would explain why this error hasn't been spotted by anyone else! :P

So, it could be that it is caused by the debug enviroment slowing things down so that the font manager is starved of input somehow. Cameron, try running in debug a couple of times and clicking the text tool, to see if it happens for you too?