On my system this was never an issue until the date that I started this thread and I believe there was an update. Also your thesis does not explain why we all see the line only on the right and bottom of our screens
I have that problem with ET 2.8.8 on Win7. It's a version of ET from last year.
As for why the border is only on the right and bottom, it's an OS bug, not a feature. Windows shouldn't display those lines at all. If it was the result of a single factor, it would have been fixed long ago. The problem doesn't (can't) happen with exclusive mode. In windowed mode there is some work-around but it still the result of an OS bug and not of the software so don't expect consistant result.