Clicking "Back To Edit" button when previewing a page in maximized view causes the bottom bar to be displayed only partially

Steps to reproduce

1. Edit a page in WYSIWYG mode (not in-place)
2. Un-tick "Allow Realtime Collaboration" box
3. Click "Leave the collaborative session" button
4. Click "Maximize" button from CKEditor's toolbar
5. Click "Preview" button
6. Click "Back To Edit" button
7. Observe the bottom bar containing the buttons ("Save & View", "Save", "Cancel")

Expected results

The bar is placed on the bottom (the view is still maximized), but entirely visible.

Actual results

The bar gets partially hidden (more than half) on the bottom.

The issue does not reproduce if the realtime editing mode is not activated.

Reproduced also on XWiki 16.4.6 with realtime editing mode active (it's not activated by default).