Hi,
I did not know what SMPlayer's "Compact Mode" did, so I tried it.
Wow! (Nearly) all the controls and toolbars disappeared, and there was absolutely no hint or option to get them back. Even shutting it down and restarting it didn't work.
If if weren't for the fact that I've got it on my laptop too, was running it there (to be able to tell you which version of SMPlayer I was using), and noticed the hotkey "Ctrl C", I would have had to wait for someone on this forum to tell me how to toggle this "feature". Hmm.
For the sake of non-techies, I'd =strongly= suggest you put some sort of "un-Ctrl-C" in the one remaining Title Bar.
Cheers,
Carl Turney, Christchurch, New Zealand