seems like the new clipman plugin forces symbolic icons however it should follow the -gtk-icon-style setting of the current GTK3 theme/panel setting. https://mail.gnome.org/archives/commits-list/2014-May/msg03435.html for example: #xfce4-clipman-plugin image{ -gtk-icon-style:regular;} has no effect. also have a look at the pulse audio plugin which works nicely with both settings(except the notification that suffers from the same issue): eg by switching: #XfcePanelWindowWrapper button>image{ color:@darktext; -gtk-icon-style:symbolic;} -------------------------------------- also the best way would be to default to regular icons(if not set to symbolic by the GTK theme) since the most X11 icon themes does not support symbolic icons(they are only used by GNOME and its apps), also the most systray icons does not use symbolic icons either(Qt-apps, electron apps, etc.) resulting in a inconsistent panel with mixed symbolic and regular icons.
I think this is because its missing the non-symbolic icon. Copying: /usr/share/icons/hicolor/scalable/apps/xfce4-clipman-plugin.svg ...to: /usr/share/icons/hicolor/scalable/apps/clipman.svg ...and rebuilding the icon cache makes it work with "-gtk-icon-style: regular;" The fix for this is in the git tree is to make a copy of https://git.xfce.org/panel-plugins/xfce4-clipman-plugin/tree/data/icons/scalable/xfce4-clipman-plugin.svg to clipman.svg and make sure it gets installed.
well creating a clipman icon works however is there any reason why the icon does not follow freedesktop naming(https://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html)? for example it should be something like: xfce4-clipman-plugin & xfce4-clipman-plugin-symbolic or edit-paste & edit-paste-symbolic or utilities-clipboard-manager & utilities-clipboard-manager-symbolic
As ToZ showed, you can define the icons as non-symbolic as long as your icon theme provides an icon of the correct name. FYI the "clipman" icon name has been around forever, edit-paste was only added as a fallback.