Xcode 11.2 assistant layout greyed out

Question

I can't change the layout of the assistant editor in Xcode 11.2. So the matching code of the storyboard is always on the right which drives me crazy bc I'm working with 21" screen. The phenomen appears when updating Xcode from 11.1 to 11.2. The Layout can be seen, but its greyed out. I cannot choose the available options Editor on left , Editor on top. I've tried to change editor orientation, but have no success. Opening a second editor below shows the assistant editor of the new editor pane on the right too?!

Answer 1

You might've accidentally enabled Focus Mode which I just realized was the reason I couldn't open additional Editors:

Turn Focus Mode off and you should be able to add Editors as expected.