When the editor window is in the background, clicking into it behaves very inconsistently with regards to making it the active foreground window.
Below is a screenshot with some markings. The IDE window is in the foreground, with the editor still visible behind it. Clicking into the red areas doesn’t make the editor the active foreground window. Some of the features can still be accessed though. For instance clicking a tab will change to that tab, but still leave the editor behind the IDE window. Clicking into any green area will activate the editor as expected.
I would expect ANY click into a window to make it the active one.
PS. I’m on a mac.