I have the Alt+Tab problem on a new Dell Precision Tower 5810. Bruce Dowson's solution works perfectly for me but the fact of the matter is that the bug remains. It is Win7 64.
Here are a few other things I have noticed. I do not have any of the programs mentioned that cause the problem, only IE11 is doing it on my machine. The computers at work, a US military base with extremely hardened Win7 64 PCs, never experience this problem,
I used them as a regular user with very limited rights. On my own computer at home, while I was setting it up as Administrator, I never saw the Alt+Tab bug. The bug only occurs when I use my new home PC as a regular user. And it happens a lot, always caused
by an IE11 window.
It seems that MS Corp. have no motivation to solve this issue since they have been pushing Win8 and now 10.