Issue with GUI and resolution change

[Seeds]

I am working on a pause menu for emulators, when the user presses a button, the menu checks for the current resolution and changes it's Width and height to the same before popping up on top of the emulator. The problem I am having with this emulator is that it will detect when it is not the active window and adjust back to the default desktop resolution. When my gui pops up, it is much smaller than the screen resolution.

I can think of two possible work a rounds, but I am not completely sure how to do either.
1. The most ideal- if I were to somehow trick the emulator into thinking it was the top most window in focus at all times this way my gui will pop up in the same resolution that the emulator was in, at the correct size.

2. Somehow force the resolution to not change when the emulator tries to change it back to the default desktop one. I would have to be able to toggle this setting off and on, so that when the emulator closes it can still change the resolution back to the regular desktop one.