I'm using xfce4-panel v4.8.1. My setup is a x-server with 2 several screens (:0.01 and :0.1) on two different graphic cards. The panel starts on the main screen :0.0 on startup. Of course I want to have another panel on the other screen :0.1. If I add a panel, it appears on the main screen :0.0 and I can select "Display 1" and "Display 2" as the output. As soon as I select "Display 2", the panel crashes with the following message: $ xfce4-panel xfce4-panel-Message: no valid position defined The program 'xfce4-panel' received an X Window System error. This probably reflects a bug in the program. The error was 'BadMatch (invalid parameter attributes)'. (Details: serial 6021 error_code 8 request_code 1 minor_code 0) (Note to programmers: normally, X errors are reported asynchronously; that is, you will receive the error a while after causing it. To debug your program, run it with the --sync command line option to change this behavior. You can then get a meaningful backtrace from your debugger if you break on the gdk_x_error() function.) Then it restarts immediately without the new panel. So there is no chance to add a panel on the second screen.
Could you attach the output if the panel with PANEL_DEBUG=1 exported in the environment? (run "PANEL_DEBUG=1 xfce4-panel > ~/panel-7217.log" in a terminal). You can also drag to another screen, maybe that works? Else you can change the xfconf property using 'xfconf-query -c xfce4-panel -p /panels/panel-0/output -t string -s screen-0' (adjust panel-0 and screen-0) when the panel is not running.
Created attachment 3450 Debug messages PANEL_DEBUG=1 xfce4-panel > panel.log
Dragging the panel to the other screen yields to the same error. If I set the output-name via xfconf (xfconf-query -c xfce4-panel -p /panels/panel-1/output-name -t string -s screen-1) the panel crashes immediately on startup. I had to reset the output-name to screen-0 to get it back working.
Mmm strange, could you make a backtrace of the crash when when setting the screen with xfconf-query? Did this work with the 4.8.0 panel?
Created attachment 3451 Debug messages (xfconf-query settings) $ xfconf-query -c xfce4-panel -p /panels/panel-1/output-name -t string -s screen-1 --create $ PANEL_DEBUG=1 xfce4-panel 2>panel1.log
Hmm... good question. It worked until I did a upgrade. But I don't know whether I used 4.8.0 before. I'll check if the error also occurs on the machine at work.
No i meant a backtrace; so (if possible) compile the panel with debugging enabled (--enable-debug=full) and then run 'gdb xfce4-panel' in a terminal, wait for the crash en then type 'bt' and leave the debugger with 'quit'. Attach th output in this bug.
Ok, I checked out the lates git-version of the panel and compiled it with full debug. Sadly I cannot determine a backtrace since the panel does not really crash! It "just" exists with code "01": (gdb) run Starting program: /home/matze/Downloads/xfce4/xfce4-panel/panel/.libs/xfce4-panel [Thread debugging using libthread_db enabled] xfce4-panel-Message: Plugin datetime: The "X-XFCE-Module-Path" key is ignored in "/usr/share/xfce4/panel-plugins/datetime.desktop", the panel will look for the module in /usr/lib/xfce4/panel/plugins. See bug #5455 why this decision was made xfce4-panel-Message: Plugin quicklauncher: The "X-XFCE-Module-Path" key is ignored in "/usr/share/xfce4/panel-plugins/quicklauncher.desktop", the panel will look for the module in /usr/lib/xfce4/panel/plugins. See bug #5455 why this decision was made [New Thread 0x7fffee3e5700 (LWP 15412)] [New Thread 0x7fffe5372700 (LWP 15415)] [New Thread 0x7fffe4b71700 (LWP 15416)] [New Thread 0x7fffdffff700 (LWP 15417)] [Thread 0x7fffdffff700 (LWP 15417) exited] [Thread 0x7fffe4b71700 (LWP 15416) exited] xfce4-panel-Message: no valid position defined The program 'xfce4-panel' received an X Window System error. This probably reflects a bug in the program. The error was 'BadMatch (invalid parameter attributes)'. (Details: serial 7170 error_code 8 request_code 1 minor_code 0) (Note to programmers: normally, X errors are reported asynchronously; that is, you will receive the error a while after causing it. To debug your program, run it with the --sync command line option to change this behavior. You can then get a meaningful backtrace from your debugger if you break on the gdk_x_error() function.) [Thread 0x7fffee3e5700 (LWP 15412) exited] [Thread 0x7fffe5372700 (LWP 15415) exited] Program exited with code 01. Any suggestions?
Created attachment 3460 xorg.conf to clarify my xserver layout In the case, the my x-server layout is not clear: I'm not using twinview, I have actually two seperate servers running. xfdesktop works very well. The only things making some trouble are the panel and the display-settings (it just brings the message "Unable to start the Xfce Display Settings"). I further tested version 4.8.0 and it works.... more or less. It crashes until I "clip" the panel on one edge of the display. And this time, it really crashes (it prints out a backtrace). But at least it shows a panel on both screens!
Fixed in 7bd1028.