If you have 2 monitors the full scrren preview on the 2nd monitor works as expected, the video controls only reappear when the mouse moves on to the second monitor. I realise this may just frustrate if you do not have a second monitor so I tried the following on just one monitor.
Click to undock the preview screen, click to view full screen, and wait for the controls to disappear (about 2 seconds) then you can stop/start playback using the Space bar, you can frame step back and forward using the , and . keys (no shift needed) go to front of project using Home key and end of project using the End key, and all of this does not cause the control panel to reappear. When you want the control panel back - you already know how to do that!
Alan.