That's a good idea, so I did it. After I sent "Ctrl-Alt-Del" from the "F8-menu" of xvnc4viewer (when the screen was *not* locked), TDE opened the "End session for 'ilya'" dialog (with a dragon sleeping on the moon). And that is not the same dialog as I got by pressing C-A-Del physically today.
Looks like ctrl+alt+delete of vnc is not ctrl+alt+delete from the keyboard :-)
You can try to figure out what is sent by calling "xev" and analyse the output.
Should I file a bug about it, or is there any other explanation for this behaviour?
TDE monitors the first keyboard it finds for the Ctrl-Alt-Del keypress via evdev. The only ways to make this work are: 1.) if vnc registers as a keyboard to evdev somehow (unlikely) 2.) A security hole is opened by monitoring vnc for input 3.) (best) vnc is detected and the ctrl+alt+del input requirement is deactivated
A TDE bug report on this would be a good idea.
Tim