gnome terminal hiding other windows and screensaver with dual screens

Reported by Colin Law on 2011-05-26
80
This bug affects 15 people
Affects Status Importance Assigned to Milestone
unity-2d
High
Unassigned
unity-2d (Ubuntu)
Undecided
Unassigned

Bug Description

Following updates from the unity-2d daily ppa I find that gnome-terminal windows hide other windows even when the terminal does not have the focus.
The terminal even stays visible when the screensaver activates.
Problem not seen in U3D.
Unity-2d 3.8.4.1-0ubuntu2~bzr570

Colin Law (colin-law) on 2011-05-26
summary: - gnome terminal hiding other windows
+ gnome terminal hiding other windows and screensaver
description: updated
Colin Law (colin-law) wrote :

Following further investigation I find that this only happens when I have dual monitors enabled (in extended desktop mode). Can anyone else confirm that they see this?
Can I provide further information that would be of help to diagnosis?
It is rather annoying (much more so in practice than might be thought from the description.

summary: - gnome terminal hiding other windows and screensaver
+ gnome terminal hiding other windows and screensaver with dual screens
Florian Boucault (fboucault) wrote :

Thanks for the bug report Colin!

Can you attach the file ~/.xsession-errors to this report?
Can you also try to deactivate compositing in Metacity by issuing the following command in a terminal and then log out and log in again:
$ gconftool --set --type bool /apps/metacity/general/compositing_manager false

Changed in unity-2d:
status: New → Incomplete
Colin Law (colin-law) wrote :
Colin Law (colin-law) wrote :

gconftool --set --type bool /apps/metacity/general/compositing_manager false
has removed the problem, the terminal window now disappears behind other windows as it should. Am I going to be missing something however? I am not clear what compositing is all about in this context.
Thanks for the help.

Florian Boucault (fboucault) wrote :

Compositing gives us a few useful features:
- real transparent backgrounds for windows, for example, the launcher and the dash
- antialiased shaped windows, for example the tooltips/contextual menus of the launcher
- easier access to window previews as used in the spread (= workspace switcher)

Losing it is going to be a problem I think.
Can you describe what kind of hardware you have, especially what graphics card you are using?

Colin Law (colin-law) wrote :

It is a Toshiba Satellite A100-197 laptop. For the graphics lshw shows
Intel Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller.

If I reduce the resolution on the second monitor such that the virtual display is less than 2048 (or thereabouts) then the problem disappears.

The problem only appeared following an upgrade but I do not know exactly which version it appeared at. If necessary I could revert to earlier versions to determine exactly when it was introduced if someone can tell me how to do that.

Changed in unity-2d:
status: Incomplete → New
importance: Undecided → High
tags: added: compositing
Florian Boucault (fboucault) wrote :

Confirming per duplicate.

Changed in unity-2d:
status: New → Confirmed
milestone: none → 3.8.12
Changed in unity-2d (Ubuntu):
status: New → Confirmed
Sabin Iacob (iacobs) wrote :

new laptop here (eeepc 1015pn with the Intel graphics card active, as the nVidia chip doesn't seem to support dual monitors), same problem; attaching lspci output (it's an Intel N10 chip)

Didier Roche (didrocks) on 2011-07-28
Changed in unity-2d:
milestone: 3.8.12 → 3.8.14
Didier Roche (didrocks) on 2011-08-01
Changed in unity-2d:
milestone: 3.8.14 → 3.8.16
Didier Roche (didrocks) on 2011-08-11
Changed in unity-2d:
milestone: 4.0 → 4.2
Changed in unity-2d:
milestone: 4.2 → 4.4
Didier Roche (didrocks) on 2011-09-01
Changed in unity-2d:
milestone: 4.4 → 4.6
Didier Roche (didrocks) on 2011-09-08
Changed in unity-2d:
milestone: 4.6 → 4.8
Colin Law (colin-law) wrote :

Anyone using the workaround
gconftool --set --type bool /apps/metacity/general/compositing_manager false
to avoid the symptom might like to know that, for me, this causes odd effects with drop down boxes from indicators on the panel clearing an equivalent area on the other screen to the background image (in dual screen mode). See bug #846528.

Didier Roche (didrocks) on 2011-09-15
Changed in unity-2d:
milestone: 4.8 → 4.10
Michał Sawicz (saviq) wrote :

@Colin can you confirm that you're still seeing this? I can't reproduce on two different setups.

Colin Law (colin-law) wrote :

Yes, I am still seeing it, with
gconftool --set --type bool /apps/metacity/general/compositing_manager true
then if I slide a terminal window over another window, then select the underneath window the terminal window stays on top. It is not selectable however, mouse and keyboard go through to the underlying window.
gconftool --set --type bool /apps/metacity/general/compositing_manager false
removes the problem (but introduces others).

I reported previously that I only see the problem when I have dual monitors (extended mode). In fact it only happens if the virtual desktop is >2048 wide (or thereabouts). If I configure both displays as 1024x768 it is ok, but with greater resolution I see the issue.

Michał Sawicz (saviq) wrote :

OK, got it on a netbook and 2048+ wide extended desktop. The terminal window is drawn without opacity (it's rectangular, the not-rounded-anymore corners are ~black).

What's more, on unity-3d, when I get a screen that wide, the desktop basically breaks and plays dead.

This is on a Atom netbook, Intel N10, so it seems consistent that this issue comes with lower end intel chips.

@Colin can you confirm that U3D still works as expected? @Sabin, you too, please?

To me it looks more and more as a hardware / driver issue.

Colin Law (colin-law) wrote :

@Michal: The reason it goes apparently dead on 3D is that 3D will not work on the chipset with > 2048 width as the hardware does not support the extensions at that resolution. That is why I have to use 2D :) So no, I cannot confirm that it is ok on U3D.

On 09/19/2011 05:04 PM, Michał Sawicz wrote:
> OK, got it on a netbook and 2048+ wide extended desktop. The terminal
> window is drawn without opacity (it's rectangular, the not-rounded-
> anymore corners are ~black).
>
> What's more, on unity-3d, when I get a screen that wide, the desktop
> basically breaks and plays dead.
>
> This is on a Atom netbook, Intel N10, so it seems consistent that this
> issue comes with lower end intel chips.
>
> @Colin can you confirm that U3D still works as expected? @Sabin, you
> too, please?
>
> To me it looks more and more as a hardware / driver issue.

Unity 3D (Compiz, actually) is unusable on dual monitors if the desktop
exceeds the maximum texture size (which, for Intel cards and a few
others, is 2048x2048); Unity 2D is ok if I don't use compositing (apart
from some artefacts that are drawn on the primary monitor when the
secondary/external one displays a menu), gnome terminal is drawn on top
of everything otherwise.

While it may be a hardware limitation (Intel seems to have made a habit
out of this, Atom chips can't use more than 2G of RAM, for instance), is
it really that hard to paint separate monitors in separate textures?
(disclaimer: I don't know what I'm talking about, I know nil about the
way compositing is done).

Didier Roche (didrocks) on 2011-09-22
Changed in unity-2d:
milestone: 4.10 → 4.12
Changed in unity-2d:
milestone: 4.12 → 4.14
Michał Sawicz (saviq) wrote :

Please see bug 824099 for a discussion on what can be done here.

Colin Law (colin-law) wrote :

@Michael: To clarify, is your comment about bug 824099 just the 3D issue, and so is not directly relevant to the symptoms of this 2D bug?

Michał Sawicz (saviq) wrote :

@Colin it's basically the same issue, max texture size being smaller than your desktop width. The bug linked above describes the approach taken in u3d, which probably needs to apply in u2d, too.

Colin Law (colin-law) wrote :

@Michael could you clarify what that approach is? There is quite a lot of noise in that thread and I am not sure which posts are relevant to 2D. Comment #18 seems to be suggesting that the fix is to not allow configuration of multi-head setup large enough that the problem is seen. Does this mean I would not be able to use Unity-2D in that case? Hopefully I am mis-reading this as I would much prefer the current workaround, which is to disable compositing, which only leads to minor display corruption.

Michał Sawicz (saviq) wrote :

Well, sure, without compositing we're pink, but with compositing there's one texture spanning the whole desktop area, and if the desktop area is too big, we're stumbling. And there's no (easy) way to circumvent that.

So yes, sorry, but the current situation is that we'll prevent having such a setup that causes a broken compositing environment.

Colin Law (colin-law) wrote :

I cannot believe I am reading this. We are going to go from the situation where I can use Ubuntu 11.10 with a laptop with external monitor with minor display corruption by switching off compositing, to the situation where I will not be able use 11.10 with the external monitor at all?
I hope this is well advertised so people who will find themselves in my situation do not upgrade.

Florian Boucault (fboucault) wrote :

I think there was either an overstatement or a misreading :) It is and will still be possible to deactivate compositing via the usual GConf key. I hope that clears it up.
In the meantime I think this matters deserves more investigation than just saying "it's the same issue as when using OpenGL composition". Metacity uses XRender to do the compositing and has very different code paths to Compiz. I know that ultimately it might be the same underlying issue with the hw/drivers but I believe it requires digging.

Florian Boucault (fboucault) wrote :

@Colin: do you mind trying with xfwm4 instead of metacity. It has a compositor as well and an option I still need to find to activate it. If it works well it could give us a great hint at what is wrong with metacity's.

Florian Boucault (fboucault) wrote :

@Colin: could you attach the output of xdpyinfo please?

Colin Law (colin-law) wrote :

xdpyinfo.out attached.
To try xfwm4 do I just install it? Also how do I get back?

James Gifford (jamesgifford) wrote :

Can we just move to openbox for Unity 2D in 12.04? (seriously).

James Gifford (jamesgifford) wrote :

Ugh, hit send too soon.

What I really mean is that this bug is a metacity-unity2d-gnome-terminal bug - I've been unable to replicate it while using unity2d and openbox.

At the very *least* we should have it documented that this bug doesn't appear in openbox/unity2d, so if you're looking for a temporary solution that's it.

Michał Sawicz (saviq) wrote :

@James just so you know - using metacity without compositing vs. any other window manager without compositing gains exactly nothing.

@Colin run `xfwm4 --replace &` / `openbox --replace &` to get them to manage your windows.

I was unable to turn on xfwm compositing, though...

Colin Law (colin-law) wrote :

Is there any point me trying xfwm4 then? I am happy to try things if it will help with diagnosis, but not much point unless something will be learnt by it.

Michał Sawicz (saviq) wrote :

If you can get it to do compositing - sure, that would be very interesting to know.

Colin Law (colin-law) wrote :

Unfortunately that assumes that I would have some clue as to where to start to get it to do compositing :)
If you were unable to is it likely that I would?

Michał Sawicz (saviq) wrote :

If you had more than 30s, as I did, to spend on it, probably! Starting point - google, as usual :)

Colin Law (colin-law) wrote :

No luck getting compositing going in xfwm I am afraid.
It seemed to me that it should be on by default, but I tried
I tried xfwm4 --compositor=on --replace &
and I tried creating /etc/X11/xorg.conf (there was not one before) containing
Section "Extensions"
    Option "Composite" "Enable"
EndSection
and logging out and in and doing the xfwm4 command (with compositing again)
but to no avail.

Google has not provided any other suggestions.

Colin Law (colin-law) wrote :

Just as a matter of interest is it known why it is only (as far as I know) gnome-terminal that shows this problem? Perhaps there is a clue there.

Colin Law (colin-law) wrote :

Having said that I have failed to enable compositing in xfwm, I am not entirely sure that I know how to tell when it is enabled. What would I expect to see?

Sabin Iacob (iacobs) wrote :

On 10/18/2011 06:46 PM, Colin Law wrote:
> Just as a matter of interest is it known why it is only (as far as I
> know) gnome-terminal that shows this problem? Perhaps there is a clue
> there.

because probably gnome-terminal is the only commonly used app to have
compositing transparency on by default; if that were changeable (I
remember in the good old days there were some apps that let you change a
window's opacity when using compositing, couldn't find one these days;
consistent with the Gnome mindset of "users are stupid, let's disable
all controls", mind you...)

Gerry Boland (gerboland) on 2011-11-21
Changed in unity-2d:
milestone: 4.14 → none
Colin Law (colin-law) wrote :

I am still seeing this problem in 12.04.

I also see this problem. Unity 2D, 12.04, dual-display width > 2048. Terminal won't ever go behind other windows. In addition, the terminal stays in front of its own menus, so the menus are unusuable, and also stays in front of any pop up dialogues (e.g. the one which says that a process is still running and do you want to kill it).

This bug has been annoying me for at least the last 12 months, I think from the first time I installed Unity 2D.

Colin Law (colin-law) wrote :

@Charlie, just in case you missed it, the workaround in comment #4 fixes the problem for me and does not seem to have any significant side effects. Not ideal I know but much better than nothing.

Péter Trombitás (trombipeti) wrote :

Also, as another workaround, I use Guake from now on. It hides, so it's
good for me. And you can start searching for terminals that doesn't produce
this (Xterm is one of them :)). So you can enjoy unity-2d with a resolution
> 2048*X

2012/4/8 Colin Law <email address hidden>

> @Charlie, just in case you missed it, the workaround in comment #4 fixes
> the problem for me and does not seem to have any significant side
> effects. Not ideal I know but much better than nothing.
>
> --
> You received this bug notification because you are subscribed to a
> duplicate bug report (963437).
> https://bugs.launchpad.net/bugs/788607
>
> Title:
> gnome terminal hiding other windows and screensaver with dual screens
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/unity-2d/+bug/788607/+subscriptions
>

Colin Law (colin-law) wrote :

For the record I find that the workaround in comment #4, which disables compositing, can have the side effect of messing up the background of the launcher. See bug #960366. At the moment this is the only side effect that I have noticed.
Interestingly the problem described in comment #9 (bug #846528) seems to have gone away.

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