Drag & Drop on xinerama multimonitor - offset problem

[Jan-Jonas Sämann]

When dragging files or contents on Unity desktop in multi monitor environment (3 monitors horizontal) they will get dropped
one monitor wide left beside the cursors position.

I expect that files and contents will be dropped at the cursors position and not one monitor wide left hand side of the pointers
position.

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D Her (p4r4code) reports:

I have the same Problem!
I am using the NVIDIA Quadro 450 NVS with 3-4 Monitors. The Problem occurs with 2-4 Monitors enabled. Only files or icons on the desktop or within folders are affected, but Windows itself are not.
I am running Ubuntu 11.10 86_64.
I posted a detailed description including my Xorg.conf here: http://ubuntuforums.org/showthread.php?t=1916670

Please could you fix that bug somehow?
Thanks a lot!

[Sebastien Bacher (seb128)]

Thank you for your bug report, setting low since xinerama is not something strongly supported nowadays, xrandr is the recommend way to use multiple screens

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Stephen Birch (sgbirch)]

This should be a higher priority. AFAIK you cant use randr to control three screens if you have two adapters, xinerama is still the only option ... and this bug!

[jonim8or (ongewenstepostberichten)]

I have a quad-screen Xinerama setup, using two nvidia cards. This bug also happens in gnome-classic, so it could be a gnome issue?
What happens for me, is that the dragging position is offset with one screen height(1024 px) to the top. So if I start dragging a desktop icon in one of my two top screens, it disappears. But when I drag it all the way down so that my mouse cursor is on one of my two bottom screens, the Icon appears on the the corresponding top screen. That is also the place where it will be released.

This bug also occurs when dragging panels btw. I don have any panels on my bottom two screens in gnome-classic, because I can t get them there.

[jonim8or (ongewenstepostberichten)]

Just checked. Under XFCE this also occurs when dragging nautilus files, but not when dragging toolbars or when dragging files from Thunar. Dragging files from Thunar to Nautilus works fine, but when dragging from Nautilus to thunar the offset anomaly happens.

[dimension128 (dimension128)]

I don't understand why people are so quick to disregard users of xinerama. I'ts not our fault nvidia won't support randr fully.
I can still connect an old scanner from 2003 and Ubuntu works with it perfectly. Why don't we have the same attitude with xinerama?
This bug is seriously annoying.

[Stephen Birch (sgbirch)]

This bug is driving me CRAZY. After over 15 years with Linux the
constant stream of annoying bugs is making me start to consider
windows again. The number of broken things jangles my nerves.

On Wed, Jan 11, 2012 at 1:03 PM, dimension128 <email address hidden> wrote:
> I don't understand why people are so quick to disregard users of xinerama. I'ts not our fault nvidia won't support randr fully.
> I can still connect an old scanner from 2003 and Ubuntu works with it perfectly. Why don't we have the same attitude with  xinerama?
> This bug is seriously annoying.

[Sergio Oller (zeehio)]

In my case I just wanted to move 5 or 6 icons from Left screen to the Right Screen. I could finally move them with a bit of luck:
1. Right click on the desktop and use the "Keep aligned" option.
2. Select the icon on the left screen by clicking not in the middle of the icon but as on the left as possible.
3. Move it to the right as much as possible, so as it gets in the middle of both screens (as much as possible).
4. Enlarge the icon (Right click option)
5. Try to move it to the right, if you are lucky (I had to try for 20-30 seconds) the icon will align on the first column of the right screen.

Tips and limitations:
Try using a long icon name.
Don't move again the icon, it will go back to the left screen.
Only the first column of the right screen is reachable with this workaround.

[Stephen Birch (sgbirch)]

It would be great if this was fixed in time for the new LTS :-)

[jeff millar (wa1hco-l)]

I have the same bug with a simple dual screen setup using an Nvidia graphics card. The initial install worked correctly, but stopped working when I plugged in an HDMI cable between the graphics card and one monitor. Maybe that tidbit of info will help with the debugging.

More bug details. Moving windows works correctly. The only thing that obviously doesn't work in moving files or folders in nautlius or on the desktop. When clicking on a file or folder, the object appears invisibily way off to the left and doesn't appear on screen until moving the mouse way to the right. A similar thing happens when starting from the right screen.

[Jan-Jonas Sämann (janjonas)]

The same problems occur, if you have to drag selected text snippets in the text editor gedit

[Ninwa (jbleau)]

I'm also affected by this problem using a dual-monitor setup with Xinerama. I have an older Nvidia card and I'm using both of its outputs to two monitors, one using DVI and the other VGA. This really is my only constant frustration. Windows 7 handles the card and monitors perfectly.

[jonim8or (ongewenstepostberichten)]

Added a video to show the problem.

Even though xinerama may be old, please work on A solution for multiple graphics cards on ubuntu.
http://youtu.be/kIvcuhZp6Q8

[emlodnaor (emlodnaor)]

I found a fix for this problem! :)

The trick is to arrange the monitors the order that your computer does.

When i had the problem, my monitors where in order 3, 4, 1, 2.
I rearranged them so they are now 1, 2, 3, 4.

First I went to xorg.conf and dissabled xinerama, then restarted, and used AMD Catalyst Control Center to rearrange my monitors based on the indentifying numbers. Remember to edit resorlutions too. Reboot and you should be done :)

[emlodnaor (emlodnaor)]

NB: not sure if this works in anything but landscape setup

[jonim8or (ongewenstepostberichten)]

I don't have AMD, I have nvidia. How can I find out the "order of the monitors"? are those the numbers the nvidia-settings tool gives them?

I have them arranged as:
3 4
1 2
1 and 2 are straight up, and on my 1st graphics card
3 and 4 are upside down, and on my 2nd graphics card

I have the problem when dragging Items that are on my monitors 3 and 4

[emlodnaor (emlodnaor)]

Yes it's the numbers the tool give you, as i said, not sure it would work for you, i have landscape, but play around with and see if you find something that works for you...

i would try

1 2
3 4

[jonim8or (ongewenstepostberichten)]

You're right, the setup
1 2
3 4

fixes this. It is however still weird that any different order of screens introduces bugs, but well... I can work for now.

[Stephen Birch (sgbirch)]

YES!!!! Thank you emlodnaor, your fix also solved the problem on my two card, three monitor NVidia configuration.

Using the "NVIDIA Server Settings" tool ($sudo apt-get install nvidia-settings) to arrange the screens so their sequence is 0, 1, 2 did indeed solve the problem for me. Cursor jumping is gone and drag and drop now works without an offset cursor. Starting to like precise now.

One thing, I could not see from the NVIDIA tool how to identify the screen numbers so I resorted to a little trial and error.

[Jan-Jonas Sämann (janjonas)]

OpenGL version string: 4.2.11627 Compatibility Profile Context
In Xinerama mode