@lah7
Since I kept the desktopfiles, that i changed, in $HOME/.local/share/applications
(which actually works) I never noticed that.
But for this cause, I just deleted them and made the changes in /usr/share/applications
and indeed it doesn't follow the settings in ayatana-settings.desktop
It is, however, not hardcoded:
Tracing links back and forth, I discovered there is another .desktop file: /usr/share/mate/applications/ayatana-settings.desktop
which indeed has the line Icon=system-component-addon
If the patch is made against /usr/share/mate/applications/ayatana-settings.desktop
instead of /usr/share/applications/ayatana-settings.desktop
I bet there is a high probability that it will work
Sorry that I can't send you a pull-request (I don't have a github account, and to be honest I don't even know how it works ) but I hope you can do something with this info.
EDIT: Changing that desktopfile will probably damage other themes so I guess that the Ambiant-MATE icon theme needs a copy of (or softlink to) ayatana-settings.svg
named system-component-addon.svg
or something like that