switch from user-side.
if user will symbolic icons on panel, all good,
if user will regular icons on panel, he can add:
/* xfce4-Panels button-style */
to the gtk-contained.css in /usr/share/themes/"Theme-name"/...
then the better option to switch the used icon will be to check out ( in /panel-plugin/main-panel-plugin.c and/or in /panel-plugin/main-status-icon.c )
if gtk_theme_has_set to use regular style for icons,
if not; then use the symbolic-icons for clipman-symbolic.svg
use the regular icons for xfce4-clipman.png
not only check if icon exist on icon-theme
i am not a coder,
but i think a static setting to symbolic is not welcome on all user's themes
so please forgive me this idea, if this not posible
I must say I don't understand what happens here but clipman icon (panel applet, not standalone application) looks kind of different of anything else:
I just upgraded to 4.14, so not everything looks perfect yet... but... as you can see, for now I'm using oxygen icons. Oxygen has:
cat oxygen/index.theme |grep Inherits
In hicolor there's:
I found following desktop files:
[root@linux apps]# pacman -Ql xfce4-clipman-plugin |grep desktop
All of them say that:
However, my clipman plugin uses ./hicolor/16x16/apps/clipman-symbolic.svg
I'm not 100% sure, but isn't it a bug?
The icon that is used is by default just called "clipman-symbolic", so if your icon theme contains an icon by the name "clipman" and you add those lines to gtk css it should work.
See also this duplicate issue for reference: https://bugzilla.xfce.org/show_bug.cgi?id=13408