Whether I try the -l or -a option of xfce4-screensaver-command I get
the same result, a lock screen with the f29 wallpaper and a nice
login/session switch dialog (just in case, not being ironic here). I'm
not sure how to get a blank screen and so far setting the timer to 1
minute and leaving the laptop alone doesn't seem to be enough. If I
lock the screen (and get the login dialog) then eventually it goes
blank.
I managed to get rid of this weird behavior by undoing changes I made
to my power and display management, because for some reason I would
never get the proper behavior with xscreensaver. For example when
watching a video the screen would eventually lock itself if I don't
press keys... That seems to work better with xfce4-screensaver, I have
yet to witness this while watching a video with the laptop unplugged
and running solely on battery.
It happened once, and when it did I could no longer use the
keyboard. If anyone is running into this my workaround was to click
"Switch User" and enter my ongoing session from there.
I was also able to reproduce this bug! My Xfce is set up to lock the
screen when the lid is closed, but if I have a right-click context
menu open when I close the lid, the screen won't lock. As soon as the
context menu is gone the screen locks and I can no longer use my
keyboard without my workaround.
I also use docky^Wplank and once that happens, plank no longer sees
open windows of a given application and clicking an application icon
always launches a new instance.
Even with that, for my usage xfce4-screensaver is already a net
benefit over xscreensaver!
Dridi