Version 16.0 (16.0.0.255)
The F2 preview does not work.
I also tried re-assigning the preview key to Ctrl+F2 but that doesn't work either so I set it back to just F2 which still fails to work.
Even stranger;
With a .html file nothing happens
With a .css file it opens a new tab with prev0~.htm file
With a .js file it opens the file in notepad