How can I stack editors vertically in Xcode 11?

Question

The option to stack editors in Xcode 11 has been moved to Editor-Layout in the menu. However the three options Automatic/Editor on Left/Editor on Top are greyed out. How can I unlock this to arrange editors in a vertical stack?

Answer 1

TL;DR: In the top bar menu under View, click Change Editor Orientation.

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• Option #1: In the top bar menu under View, click Change Editor Orientation.
• Option #2: In the File Navigator, press Command + Option + Control + T to open the currently highlighted file in an editor below the currently active editor. This orientation switches to horizontal if the Change Editor Orientation option was set.
• Option #3: At the Open Quickly prompt (accessible by pressing Command + Shift + O), search for a file without pressing Return and, when a file is highlighted, press Option + Shift + Return. Use the arrow keys to specify where the new editor should be located.