Does not work well with steam windows that do not have static window names I guess.

[x3style]

It seems it's using windows title names to identify them, does not work well with Steam windows.

[Todd1561]

I'm not familiar with Steam but this is likely the same issue that's outlined here https://github.com/Todd1561/TANWindowMgr/issues/14 unfortunately I've yet to find a fix. This app tracks windows by their underling process/exe name. My guess is there is one Steam process and it's spawning multiple windows, which doesn't work with this. The only way around this I can think of is to re-write the app to identify windows based on their display text, but that can change wildly depending on the app. Chrome is a good example as it changes with the title of the active tab.