`spawnOverlay` doesn't have checks for special cases (e.g. `singleInstance`) 

Take AcceleratorOverview for example. It is a SingleInstance app, as you know, and can be opened from the desktop, then if you use CTRL+/ it will open it again, despite it being SingleInstance.

~~Accelerators don't~~ `spawnOverlay` doesn't take `elevated`,`spawnCondition` or `singleInstance` into account.