[Leroy Casterline]

I ran into the same issue and found this thread yesterday, which led me to believe I was mis-remembering how things used to work. Today, completely by accident, I found the solution.

Zooming works as you wish in one of the two full screen modes (‘full screen mode’, ‘full screen mode with menu bar’), but the other way, in which the image centers when it will fit on the screen, in ‘standard screen mode’.

You can cycle between modes via the ‘F’ key or ‘shift-F’ key depending on your preferences; you can also switch between modes via the icon on the toolbar.