I use KWin, and it has configurable keyboard shortcuts for basically everything, so I have ones configured to effectively tile windows into halves or corners of

I use KWin, and it has configurable keyboard shortcuts for basically everything, so I have ones configured to effectively tile windows into halves or corners of the screen. This makes very good use of 16:9 monitors. But sometimes an overlapping window is very useful. For example, I'm watching a fullscreen video, but I want to chat with a friend in an instant messaging app. I can put the conversation window on top of the video in a corner of the screen where it doesn't block anything important. Or I'm doing some kind of graphical work, image editing, web design, etc, and I only need to see part of a window, but it needs to fill the height of the screen. I can put other programs on top of the parts I don't need to see. Tiling is great, but overlapping windows have their place too.