I can actually reproduce the problem now. An incorrectly set environment variable caused my xfconfd to use Libxfce4util 4.16.x instead of 4.17.x on my system. Dev machine…
Every time I change panel configuration a comma is written as a decimal separator to "double" type values, e.g. panel length, to ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-panel.xml and it breaks the panel after reboot or relogin. If I edit the configuration file by hand and replace all commas with dots in "double" type values panel is OK after reboot or relogin.
In my locale fi_FI.UTF-8 a comma is used as a decimal separator. glibc version is 2.36, and glib version 2.74.0.
It's weird, my locale is fr_FR.UTF-8 (for which a comma is also used as decimal separator) and I never had this problem. So I'm going to need more info here.
Could you (anyone who can reproduce this problem) give the output of xfce4-panel --version and xfconf-query --version, both for the panel version that works correctly and the one with the bug.
To be sure please try to change the settings of the listed applications and run this command again, to see if they don't have the same behavior when saving.
No, libxfce4util 4.17.3 used for the both greps. There was only about a minute between the greps. Everything seems to be working until settings are altered.
I'm using Mageia Cauldron, the latest development version of the distribution.
Ok thanks, I think I got it. Ultimately it's a problem in Xfconf, which was revealed by a recent change in Libxfce4util on which it depends. I will provide a fix soon.
Could you please describe which combination of libxfce4util and xfconf revealed the bug and which combination has fixed it? I was running into empty panels with xfconf-4.17.1 and libxfce4util-4.17.3 while I read here that xfconf-4.17.1 already has the bugfix.
It might be that the damage here was happening earlier with xfconf-4.17.0 but not appeared somehow due to delayed restart and not solved by 4.17.1...
Anyway, for this kind of bugs I downgraded back to stable Xfce 4.16* on Gentoo.