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Windows resize improperly and instantly span multiple displays


Description Anthony Symons 2012-01-09 05:38:48 CET
Created attachment 4090 
xfce4-1.png xfce4-2.png xfce4-setup.png etc/X11/xorg.conf

Reposted from the fedora bugzilla at request to post it upstream. Fedora bug can be found here:


Description of problem:

Some windows in some apps have a habbit of expanding across multiple screens
when they shouldnt on a bottom right hand corner resize. left border or other
corners seem ok, although sometimes the whole window jumps when draging from the title bar. 

Apps that are affected:

eye of gnome

Apps that are not affected:
Terminal (the default Xfce4 one)

Version-Release number of selected component (if applicable):


How reproducible:

90% of the time (occasionally things work properly, but very easy to reproduce
on my system)

Steps to Reproduce:
1. Open an affected app, eg gedit-3.2.5-1.fc16.x86_64
2. Position mouse pointer as in xfce-1.png screen shot (note that the icon in
the screenshot is not the icon on the display - on the display the arrow starts
top left of the pixel being pointed to and points down/right to the location. 
3. Drag the corner of the window.

Actual results:
Mouse cursor stays in the right spot, but the window expands across multiple
displays to the same relative pixel but on a screen or two to the right. 

Expected results:
normal window resizing

Additional info:
slightly non-standard display config is likely a critical factor - but it
should still work). 

Displays are running proprietry nvidia drivers. But I dont think this is
a factor.

For screen config see xfce4-setup.png

Left screen the first display on the 2nd card.
Middle screen is 2nd display on the first card.
Right screen is 1st display on the first card.

See xfce4-1.png for the display immediately before the drag, and xfce4-2.png to
see what happens to the window on a slight resize.
Comment 1 Olivier Fourdan editbugs 2012-01-09 11:13:39 CET
This seems to be specific to the use of resize grips from gtk3 applications (apps listed as working are gtk2).

I am not sure this is really a xfwm4 bug as the positions is taken from the XMessageEVent sent by the application itself (see [1]).

Does the same happen with other window managers such as metacity or kwin?

(you can try replacing xfwm4 with "metacity --replace" or "kwin --replace) for a quick test, then restart xfwm4 with "xfwm4 --replace --daemon")

It would also be worth trying without the poprietary NVidia driver as the pointer position is influenced by the monitor layout, which is quite specific in NVidia proprietary driver if I am not mistaken (to be clear, I cannot reproduce with intel open source driver even with a multihead setup similar to yours).

[1] http://standards.freedesktop.org/wm-spec/wm-spec-1.4.html#id2551196
Comment 2 Anthony Symons 2012-01-10 01:10:04 CET
This bug still exists when using metacity as a WM. 

It also still exists when using the nouveau driver. I'll copy up the info here to show I am using the right driver for the record so you can see I got the swap back right :)

[root@ant ant]# lsmod |grep no
nouveau               754554  3 
ttm                    61533  1 nouveau
drm_kms_helper         30277  1 nouveau
drm                   213647  5 nouveau,ttm,drm_kms_helper
i2c_algo_bit            5572  1 nouveau
mxm_wmi                 1743  1 nouveau
video                  12388  1 nouveau
i2c_core               28203  5 nouveau,drm_kms_helper,drm,i2c_algo_bit,i2c_i801
[root@ant ant]# lsmod |grep nv
[root@ant ant]# 

To do this, I yum remove kmod-nvidia, then since the .ko seemed to still exist and be loading I rm'd them by hand. I also edited xorg.conf and changed all the driver references from nvidia to nouveau. The screens arnt perfectly correct - the right one is completely blank though not in power save mode (probably because there is now no twinview), but the bug is reproducable with this configuration. I'll omit screen shots - it looks like before except when the window jumps out to the right it extends off the right hand side of the middle screen (out of the viewable display area). 

Feel free to change the component this bug is listed against.
Comment 3 Anthony Symons 2012-01-10 02:12:51 CET
Ok, it looks like its not xfwm or xfce4 related. I just did a huge yum groupinstall KDE and I am able to reproduce with gedit on KDE, - no xfce components at all. 

Any idea where I should take this bug now?

Thanks for the time considering it.
Comment 4 Olivier Fourdan editbugs 2012-01-10 07:50:20 CET
If that occurs with both Metacity and kwin as well, then it's not xfce.

Most likely the mouse driver.
Comment 5 Olivier Fourdan editbugs 2012-01-10 08:15:20 CET
(In reply to comment #4)
> Most likely the mouse driver.

Now thinking about it, if that affects only gtk3 apps and only when using the resize grip (as comment #0 and thge screenshots implies) then it's rather a bug in gtk3 code for the resize grip (upstream has a few bugs listed, check bugzilla.gnome.org)

Bug #8315

Reported by:
Anthony Symons
Reported on: 2012-01-09
Last modified on: 2012-01-10


Olivier Fourdan
CC List:
1 user



xfce4-1.png xfce4-2.png xfce4-setup.png etc/X11/xorg.conf (4.10 MB, application/x-zip)
2012-01-09 05:38 CET , Anthony Symons
no flags

Additional information