Question

I have a fullscreen window, and I want to prevent pop up windows that appear at the right bottom corner of my screen. I set the Topmost property to true, but apparently it does not help. I also tried activating the form and giving it the focus once it got deactivated, but that did not help either. What is a way to ignore such windows while the user is engaged with the fullscreen app? I am .NET programming in C#.

Answer 1

You can’t do it, this fails the “what if two programs tried to do this” test:

1. those popups are just normal windows like yours, they also use the same top-most style you are using.
2. if there was a way to always be above other topmost windows they would have used it too rendering it useless (because the authors of the other apps are just as concerned about the user missing their “super important” notifications as you are about them interfering with your full screen app).

You can try and play dirty tricks to force your window to the top of the top-most z-order, but those popups are likely to use the exact same tricks, again making this all useless (and as an extra bonus all those dirty tricks can turn your app into a compatibility nightmare).