Product and version FileMaker Pro Advanced 14.0.3
OS and version Mac OS X 10.11.1
Full Screen crashing the Dock
How to replicate
Open any solution.
Make the window Full Screen.
Create a New Window.
Make that Full Screen as well and merge into Split Screen.
Un-FullScreen one of them.
Try closing the one left on Full Screen and you get crash of the Dock.
To restart the Dock slide up 3 fingers on the mouse.
Just exit Full Screen on all windows before closing.