Blur effect not working - multi monitor.
Hello, I am opening bug as per request.
I have attached 2 screenshots showing an issue relating to setting a sigma value. When it is above 0 then you do not see a background on secondary monitor, at least for me.
Please see 2 screenshots:
Kind regards
Peter

Not sure if relevant but the desktop background is 9MB in size.
here is picture of background I am using:

EDIT: I tried a different smaller picture and had same issue so guess not.
Thanks for the issue! This seems weird, the sigma value should not change a lot of things...
In looking glass (alt+f2, then lg), could you give me the output of the following lines?
Main.layoutManager.overviewGroup.get_child_at_index(0)
Main.layoutManager.overviewGroup.get_child_at_index(1)
Main.layoutManager.overviewGroup.get_child_at_index(0).get_effects()[0]
Main.layoutManager.overviewGroup.get_child_at_index(1).get_effects()[0]
And, when you have a non-zero value of sigma, try this and tell me if it makes the background reappear (even with no blur):
Main.layoutManager.overviewGroup.get_child_at_index(1).remove_effect(Main.layoutManager.overviewGroup.get_child_at_index(1).get_effects()[0])
Hello,
Yes it reappeared immediately when typing that, but without a blur on the second monitor.
I have attached a screenshot with the commands and outputs. Apologies I had not used lg before so ignore the unrelated mistake before realizing how to type the commands you wanted :)

Pete
Another thing I am thinking that might be related is that I have 2 displays running off my laptop, but the laptop built in display is disabled, as I am just using my laptop with 2 external monitors. Unsure if this is relevant. Essentially the laptop monitor itself is unused but has 2 monitors plugged into it.
Also I like the purple snow/winter background you have on your example screenshot on the front page, how can I find this and download it?
Also thanks for your help and interest.
I have more information. I have noticed if I am on workspace 1 then the blur is working on all monitors on the latest update (not sure if it was before I updated but I updated today then noticed this). If I am on a different workspace like 2, or 3 or 4 then the secondary monitor does not have the blur effect.
I might have spoken too soon. Sometimes when on the first workspace it does not work, although sometimes it does, so its sometimes working and sometimes not working. Im not sure how to trigger it working and how to trigger it not working at this stage. I dont remember it sometimes working and sometimes not working before I updated.
This bug sure is weird, the sigma value should not have anything to do with how the background is displayed... What is the resolution of your monitors? And, is it possible for you to test it either with another monitor, or with another resolution or with wayland/xorg? So I make sure this is not a very specific bug, and I know how to reproduce it
Btw, the wallpaper used is one of the default wallpapers in gnome :)
ok give me a few days I will try do some testing with different setups and find if I can get it to behave differently in any way.
Ok thanks a lot!
I did find something quite quickly. If I log out and go into X11, I cannot reproduce the error. In wayland I get the sometimes it works and sometimes it does not problem. I am wondering if you have tested under wayland? Maybe you will have to click the activities button a lot of times to see it happen if you have a super fast machine, mine is a little older.
Oh ok, that's clearer now! I can't test it today (as I have a nvidia graphic card, and nvidia hates wayland for the moment...), but will try with multiple monitors on wayland soon. Thanks a lot, now I understand why it worked well for me!
No worries I also have an older nvidia card but just disabled the blacklisting so I could use wayland. I also tried removing the proprietary drivers and using nouveau and same problem. I will carry on with nouveau for a while and see what performance is like.
I disabled blacklisting by editing "sudo nano /lib/udev/rules.d/61-gdm.rules" and commenting out the blacklisting of nvidia like 3 lines down.
I have this issue with AMD on Wayland, but it doesn't appear on Xorg.
Blur only appears on secondary monitor unless sigma is 0
Also having this issue on AMD Wayland.
This definitively is a gnome-shell bug, my extension should have nothing to do with X11 and Wayland... I will need to find a working machine with Wayland on it to test :)
Does this bug happen no matter the disposition/resolution or the screens (primary one at left, right, ...)? And when it disappears, is it after for example getting out from sleep, or just without any apparent reason?
Hi,
I have switched back to X11 as I had some other things that were not working, and I had not heard from you for a while. I dont believe that is has anything to do with resolution etc and when it happens on Wayland it just is random, although it happens most of the time (90%?). I just keep clicking and it sometimes goes away for a single time or two.
One thing I would say is both my monitors are the same monitor and I noticed they both have the same serial number. I saw another gnome bug that affected me with night light and monitors that have the same serial number (because they came from the same factory and were bought at a similar time - ie in my case I bought 2 off amazon on the same purchase). Not sure if this gnome issue relating to identifying monitors and having trouble (if they have the same serial no) could be related but just mentioning it in case.
As I mentioned under X11 there is no issue and I am using that at this moment so there is no urgency to fix it other than, this might be a bigger issue when more people start using wayland so good tho have in the back of the mind now in case something comes up.
Kind regards P
Thanks for the follow-up, and sorry for taking a very long time to answer...
To be honest, I don't really now how to solve this bug, until I have a decent computer that can run wayland (if I don't find one, I will login with wayland on my own computer, but for the moment I prefer to avoid it, as I broke my setup last time I did that due to a bug with cursor being scaled down that I could not fix without reinstalling...)
What I find weird is that this bug happen with AMD and nvidia, but AMD is very well supported on wayland... So it looks like a deeper bug than "nvidia not supported for the moment", but I don't know where to search first
No worries. Also unsure.
Hi I have similar issue on X11 Nvidia. No blur in overview on my secondary 21:9 display regardless of sigma level set. The primary display is a 16:9 built-in laptop display.
I have a triple monitor setup (AMD CPU and GPU) with Wayland / Gnome 40. Both Monitor 3 (My primary) and Monitor 1 are always showing the blurred background in the overview, only Monitor 2 is sometimes showing grey background for me...
Monitor 1 and 2 are the same Model of Monitor if that makes any difference
After updating to latest version of gnome/wayland etc on ubuntu Impish branch this bug no longer exists. Propose closing issue if other people can update to the latest version and confirm this also no longer happens.
Really? That's some very great news!
I will let this open so that other people can confirm, and close it in some days if everything works OK :)
I close this issue as an update made this work, please reopen if not.
I'm facing this issue on Pop!_OS 21.04 with two monitors on xorg. The second monitor gets blurred and the first monitor gets the application overview. My system is fully udated btw
That (version of pop os) does not have gnome 40.4? This is a question.
If not, please update to gnome 40.4.
P
I am still facing this issue with a fresh install of Pop! OS 21.04, running Gnome 40.4 on xorg Using a triple monitor setup, with center one as the main monitor. When enabling this extension the blur is applied on the left monitor while the application list is on the center monitor.
I'm on Arch with gnome-shell 40.5 and the issue still persists. xorg-server 1.20.13-3
I reopen this, but don't know how to resolve this tbh...