So your saying that custom buttons prevent this issue? is this just because they are blocking the bottom corner? IE try shrinking a custom button to 10 pixels in the settings, then see if the bottom corner still causes incidence.
From the sound of it, it might be windows causing the issue, does the issue persist after you uninstall classic shell? (don't worry all your settings will be saved for when you reinstall)
If it does, then there isnt much we can offer, except to run a systems file check. If the problem goes away with classic shell, then we can troubleshoot further from there
