Split fullscreen not working?
When I hold down the green button, it doesn't shrink and do that "split screen with another app" thing. Very frustrating, it was amazing (yes, it used to work... idk what happened)
MacBook Pro 13", macOS 10.14
Question marked as
If you already have a window in full-screen view, you can still view it side by side with another window. Just open Mission Control, then drag a window onto the thumbnail of the full-screen app at the top of the screen.
Apps that need more screen space to enter Split View might display a message that they're not available in full screen. You can use a higher resolution on your display to give apps more screen space. Apps that don't support Split View at all show a zoom button 
instead of a full-screen button 
.
If holding down the full-screen button doesn't enter Split View, go to Apple menu > System Preferences, click Mission Control, and make sure that “Displays have separate Spaces” is selected.