We have been having some fun (read defects raised) with dialog windows in our WPF app. I remember when we wrote the system that showed a custom Warning Message that we wanted it to be displayed modally and not show up in the task bar. Sounds simple so far. However, if I tabbed away from the app and came back to it, the dialog was hiding. Naughty little dialog. Our fix at the time was to set Topmost = true. This just got raised as a defect because it was top most for all apps. A bit of a pain for the users as it covered up other apps (probably the bug tracking system LOL).
The fix was really simple and one the makes you feel like a bit of a tool.
Window window = new Window();
window.Owner = App.Current.MainWindow; //Or the relevant window.
window…… //set other properties.
Now that we don’t have an Orphaned window he is so much better behaved. Good little dialog.