[philistine]

This is the thing with Excel. It has such a long history that it had to invent a ton of GUI interactions. A boatload of those interactions were codified in Excel before we created standard ways of doing things that even macOS, Windows and Linux share. In that sense, the modern history of Excel is the slow regression of the app to OS conventions.

For the longest time, Excel had its own windowing system within the app. It's only recently that the Office team saw the light and let the whole OS called Windows control window management in Excel.