Mint Update Manager leaves the screensaver disabled

[KevinJMachin]

Description

When the Mint Updater runs its regular update (10 minutes after session start, then every two hours), the screensaver is left disabled. This also happens after a manual update check.

Steps to Reproduce

1. Check the screensaver is enabled, using the following command.

   $ xset q
   ...
   Screen Saver:
     prefer blanking:  no    allow exposures:  no
     timeout:  300    cycle:  300
   ...

   Note the timeout and cycle values are both 5 minutes (though they may be different on your system).

2. Open the Update Manager and click the "refresh" button. The commands sudo apt update|upgrade may also trigger this, but after some delay when the mintupdate application gets notified.

3. Examine the screensaver status again.

   $ xset q
   ...
   Screen Saver:
     prefer blanking:  no    allow exposures:  no
     timeout:  0    cycle:  300
   ...

   Note the timeout value is now zero, which means it's disabled.

Expected Behaviour

It's okay to temporarily disable the screensaver and/or power management during an update/upgrade, but these should be restored once those operations have finished.

Actual Behaviour

The screensaver is left in a disabled state.

Impact

Screensaver stops working after Update Manager has run. There may also be power management implications, but I've not tested those.

Workaround: xset s 300 after every update check.

System Details

Item	Set-up	Description / Notes
System	Mint Xia XFCE
Update Manager version	7.0.7
Power management	Unused	Essentially all disabled in the configuration, except status notifications.
Screensaver	xfce4-screensaver 4.18.3	Neither light-locker nor xscreensaver are installed.
Settings	Enable screensaver	Yes
	Screensaver	Slideshow
	Activate when idle	Yes
	Regard as inactive	After 5 minutes
	Inhibit for full screen apps	No
	Enable lock screen	Yes
	Lock screen with screensaver	No
	Lock screen with system sleep	No
	On screen keyboard	No
	Session status messages	No
	Logout	No
	User switching	Yes

[KevinJMachin]

On further investigation, the issue seems to be caused by interactions between xfce4-power-manager and xfce4-screensaver, but this depends on the various settings' combination. Since it does not seem to be related to mintupdate, please feel free to move/close this issue.