Desktop App disappears from Taskbar

Running programs show in the Taskbar of Windows.

Under certain circumstances, my RS2012 V2 apps seem to disappear from the Taskbar. I believe this is due to a given Windows settings (not sure what). This confuses the users because the active window of the app is hiding behind some other app so they start another instance of the app. Then it gets hung up in that they can’t close out of it or close it’s windows that get opened.

Is there any way that I can programatically cause the app to recognize if another instance of itself is already running?

Better yet, what Window settings should I be avoiding (those that cause a window to not appear on the Taskbar)?

Maybe this?

Jason, thanks. I wasn’t aware of that capability. I also figured out what window settings cause them to not appear on the Taskbar.