Second post in less than half an hour!

I think this bug exists because @zep might have been a bit lazy when coding cursor changes for code tabs, so instead of checking if there's an actual tab in the position, he just made the cursor change when it is in a certain square where the tabs could be. To be fully honest, I don't blame him. Most of us here are programmers and you can't say you never get lazy with something in code.

TL;DR: Cursor changing doesn't check if tab is actually there.