[paperback]

Linux Mint 20.1 / Cinnamon 4.8.6 / Calibre 5.38

Make sure that your Linux panel is on the bottom and set to "Always show panel".

1. Open the attached epub in the viewer.
2. Double click on the image to open it in a separate window (make sure the "Fit image" option is not ticked).
3. Click on the "Full Screen" button.

Expected result: The window should maximize correctly, occupying all the available screen.

Actual result: Nothing happens.

4. Close the separate window, then double-click on the image again.

Expected result: The window should maximize correctly, occupying all the available screen.

Actual result: The window maximizes incorrectly, undershooting the bottom panel. This also makes the "Full Screen" button inaccessible; to access it, the user has to set the panel to "autohide".