Windows "APPS," "STORE" Popping up at random

[epic]

So, I've been using Windows 8 since it was released and haven't had any issues like this occur, I've been using Start8 and Modernmix with no trouble.

I did a fresh installation of Windows 8.1 and have been noticing some issues with WIndows apps appearing at will. The only modifications I am using are Start8, StartIsBack+ (recently reinstalled it) and ModernMix. I've uninstalled Start8 thinking that it was the problem, also the same with StartIsBack+, but neither have shown to be the problem, unless I'm missing a setting someplace.

Also, Windows "STORE" will randomly popup without warning, either while using the computer or during startup. Becoming very annoying.

I use Modernmix to minimize the screens from the intrusive "fullscreen" microshit version. If I open PC Settings to make some changes the window will popup as exected, within a window, but if I'm in the application too long it will also popup in the upper left hand corner... I'm not too sure if this is a Modernmix issue as it was working fine in my previous installation Windows 8, but then again this 8.1.