My custom editor windows get stuck with weird top bars over time

The window was fine with the normal one tab header, but as I was iterating on it's contents it became like this!
Has anyone else had this happen while they were making an editor window? If so, what was the solution?

 

Nevermind, I just had utility window parameter set to true. Although it is weird because I was doing that the whole time, but sometimes it was still showing the window with the tab anyway.