Pressing "Hide Editor" twice hides editor permanently

[JakobKallin]

The "Hide Editor" button is automatically hidden when pressed, but it can be pressed twice by using the keyboard while the hidden button still has focus. Doing so hides the editor permanently, likely because the hide button saves the current editor width, which is 0 when the editor is hidden.

[JakobKallin]

The button has now been replaced with a single button whose label changes depending on the context. Pressing it twice simply performs one action, then the other.