Apologies for the delay in digging into this... work has been a PITA, we had a major presentation due today and it ate up more of my time than I would have liked.
But, I was able to reproduce this just now. The issue happens when you maximize the size to really big resolutions. I will see if I cant get a fix done tomorrow for it.
Until then, resize the window to something smaller, exit then restart PointBlank and it should be fine.
Its a nice bug you found, only showing up on machines using higher screen resolutions (haha makes me laugh when we had arguments here in prior versions when I made the decision to allow PointBlank to be bigger than 640x480... some folk had computers that couldnt do higher resolutions