I have the same issue with 4.5.0.1530
The following 3 windows open but minimized-
1- PegasusAstro ASCOM Drivers Hub ← I have this switch
2- ASCOM.ASCOMOmniSim.Camera Driver
3- A window for C:\Program Files\ASCOM\OmniSimulator\ascom.alpaca.simulators.exe
Setting the ignore switches didn’t resolve the pop-up windows.
Control panel > Switches > right click on any Omni switch entry > select the global settings > select switches to ignore.
Mike