In the Xfce Power Manager, there is a "Put display to sleep when computer is inactive for" option, and there is a "Lock screen when going for suspend/hibernate" option. However, I do not see a corresponding "Lock screen when putting display to sleep" option. In many (most?) environments, it is important that screens get locked even when the user forgets to do this. It's very possible that I'm just not seeing the obvious place to configure xflock4 to activate after a fixed amount of inactivity. If not, this may be a bug.
I've also noticed this. It looks like a possible workaround is to use Suspend mode rather than Standby mode for the monitor (while checking the Lock screen when going for suspend/hibernate"), but I'm not sure what the implications of that are. It would be very good if we could lock the screen on inactivity while leaving the screen in a mode where it instantly redisplays on pressing any key. Technically we have a regulatory requirement that our screens must be blank and locked when inactive for 5 minutes, so adding such a feature would be very helpful.
I was thinking about this. Some distros ship Xfce with xscreensaver which has power managing support for the screen and so is redundant with the monitor section of xfce4-power-manager. But xfce4-power-manager would need at least a lock option, then people install xscreensaver only if they want the fancy screensavers. It could be like http://ompldr.org/vZTZ0eQ or http://ompldr.org/vZTZ0eg or whatever. I personally use xautolock to lock the screen one minute later than the blanking time I set with the power manager. Just saying, as this bug is to make this a GUI-easy setting.
Or http://ompldr.org/vZTZ1Yw (without redundant comment).
I noticed that with slock, if we lock the screen and then xautolock calls it again, we won't be able to unlock it (have to login in another console and terminate it). So if this feature is found to be useful, at least with slock it probably should look if it's active and NOT launch it again. (I have no idea if this issue is present with xlock(more) too, but maybe it isn't as slock is so simple)
secipolla, I could not reprodeuce the issue you described. suckless-tools version 38-2 (slock-0.9), xautolock 2.2. xlockmore is no more in ubuntu repositories, so I can't test easily. Maybe it is a bug in some earlier version. There is new locking tool called i3lock that is not that simple. And another tool light-locker will be soon have the ability to follow screensaver settings made by "xset s": https://github.com/the-cavalry/light-locker/commit/42270ed055dfb3b586c453c83b9666d928385623 so with it (and xscreensaver) you don't need to use xautolock. However, the advance of xautolock is that it is supposed to work with any locker including xflock4. Or "xautolock -locknow" could replace xflock4, but xautolock would have to be added as a dependency for xfce4-power-manager and xfce4-session. On the other hand xflock4 does not necessarily need a daemon for a locker. There is also xdg-screensaver (in xdg-utils), which could provide some general handling of screensaver, but I am not familiar with its logic (but it is basicly a Bourne shell script). One thing to keep in mind is that xfce4-power-manager is (currently) supposed to be able to control screensaver/display power management so that "presentation mode" can work.
One bad thing about xautolock (2.2) that it cannot handle that a given locker fails i.e. returns by nonzero exit code.
A related bug report: https://bugzilla.xfce.org/show_bug.cgi?id=3770
Many of the more feature-bearing lockers actually handle timed locking, so I'd say it'd be overkill for the power-manager to offer the same option again (e.g. gnome-screensaver, xscreensaver and light-locker all do this). Consequently closing as wontfix.