Fullscreen Windowed Mode

As a dual monitor user I love that ModernMix allows me to use metro apps on a second monitor, but I find it has one flaw.

When in fullscreen mode, doing something on the other monitor makes the metro app hide. So using shift click on full screen is the only option for something without a title bar, but this has one flaw for my use.  I use DisplayFusion for a second taskbar, but this would be relevant to any similar program or even with default task bar, and the maximize without title bar ends up with the taskbar still showing.  Is there any way to have an option for a completely full screen windowed mode, or to prevent modern ui from hiding when in fullscreen?

Basically, my personal opinion is that the default behavior for shift click full screen to be closer to how a browser treats fullscreen (F11), or at least have an option to be that way.