xfce-panel does not honor "primary display" setting

The panel can't just follow the primary monitor because that would prevent people from having panels on every monitor.

Instead the output configuration is done per panel. Right click the panel -> panel -> panel preferences, and then select the output you want.

Your opinion disagres with the xfce4-settings documentation:

http://docs.xfce.org/xfce/xfce4-settings/display

See section "Primary display":

"Check this option to provide a hint to panels, docks and the desktop that the selected display is the primary display."

If you want panels on every monitor you could choose not to have a primary display selected.

Your proposed behavior anyway is not user friendly. After configuring your primary monitor in xfce4-settings you have to enter the panel settings again and configure the monitor where you want the panel. If this is true for each software (panel, docks, icons) you have a lot of configuration to do when you plug in a larger monitor (but only on your right, if the monitor is on the left you're a lucky guy).

I guess this is linked to a long running xfce bug that never made it to xfce4-panel.

https://bugzilla.xfce.org/show_bug.cgi?id=8328

Under your proposal, how would Xfce know which monitor to put which panel on, if no primary monitor was selected?

My complete proposal is the following:
 * if the field "Output" in "panel -> panel preferences" is set to something else that "Automatic" honor the user choice.
 * if the field "Output" in "panel -> panel preferences" is set to "Automatic" place the panel in the display marked as "primary".
 * if the field "Output" in "panel -> panel preferences" is set to "Automatic" and no primary display is set choose the rightmost-topmost panel (current behavior).

I've found a similar open bug in xfce4 issue tracker (with patch attached):
https://bugzilla.xfce.org/show_bug.cgi?id=9338

Seems reasonable, but note that isn't the current behavior of the "automatic" setting. It positions the panels based on monitor number (according to Gdk), but the monitor numbers change if you rearrange the monitors' logical positions, which is what causes the behavior you see. The output selection code was added specifically to fix this problem, because output names do not change if you rearrange the monitors.

It should be very easy to add a pseudo-output called "Primary" which would lock the panel to the primary monitor, regardless of which one it is.

Ok, for about one minute let's stop being programmers and let's think as a normal user.
So i plug-in my monitor. The xfce4-display-settings pops up automatically, I select a display i thick the primary checkbox, i want my panel goes there. I may not know what is the display 1 in gdk.

That said the pseudo-output "Primary" is better than nothing (I imagine you want a different pseudo-output because you don't want to change the default behavior).

Can you mark this bug as Triaged? When I have some time i can try to study the problem and prepare a patch for it. Maybe you can give me some direction on what to look.

Ah i forgot to say: if I specify the second monitor as output display, and i unplug the monitor the panel disappears...

I understand why, but really... the actual behavior is not user friendly.

I don't have the access level to mark this as triaged. You will need to propose any patch upstream. The first thing to do would be to open a bug on the Xfce tracker and set a bug watch here on the remote bug. After that you will need to propose your patch on the mailing list.

The automatic setting cannot be removed as doing so would break monitor spanning panels. I would be in favour on a new pseudo-output though, if it does not cause too many problems to implement it.

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

My install has also behaviors which I find "buggy" and which I believe may be related - I attach for info if it helps the developers:

my displays are "mirrored" by default even though this option is not ticked.
http://i.imgur.com/w9q87Bt.png

the panel displays itself on the other monitor than the primary one. The primary one is the laptop (always on), the secondary on is the dell (not always plugged)
http://i.imgur.com/ptD3vmE.png

Fixed in version 4.12.2-1ubuntu1 (18.04 LTS).

4.12.2
======
- Feature: Support for RandR's "primary monitor"
- ...

There is no 4.12.2 version?
There is only a 4.13 version?

https://github.com/xfce-mirror/xfce4-panel/blob/8e57819186ee3c2070fbcd9c8b019e1c90f33edd/NEWS

Ok. There is a version 4.12.2 that contains your commit in the hirstory.
I have version 4.12.2 but it does not work...

This doesn't work in 4.14.3-1 (Xubuntu 20.04). Setting a display as primary does not move the panels & desktop icons to it, when the other display is positioned left.

Not sure how to update this bug, since it seems to still be present on 20.04 xubuntu. I added, the settings package, as that is what xfce4-display-settings is a part of.

Willem & Daniel, I thought I was having this issue on 22.04, but I found this that fixed it: https://unix.stackexchange.com/a/149477
Turns out that in each panel's preferences, the "Output" property was set to "Automatic". Setting it to "Primary" moved the panels to my preferred display.