You can confirm the ActiveChanged signal is not being emitted by GNOME Screensaver by doing the following:
$ gsettings set org.gnome.desktop.session idle-delay 1
$ gdbus monitor --session --dest org.gnome.ScreenSaver
If you wait for one second and then the fade to complete you will see the ActiveChanged signal when the monitor blanks. If you lock the screen first with alt+ctrl+L you don't see any fade or signal.
You can confirm the ActiveChanged signal is not being emitted by GNOME Screensaver by doing the following: desktop. session idle-delay 1 ScreenSaver
$ gsettings set org.gnome.
$ gdbus monitor --session --dest org.gnome.
If you wait for one second and then the fade to complete you will see the ActiveChanged signal when the monitor blanks. If you lock the screen first with alt+ctrl+L you don't see any fade or signal.