ltguillaume
commented
7 years ago Alrighty, putting this into userchrome.css seems to do the job for me.
#openwith-contextsubmenu, #openwith-contextlinksubmenu {
-moz-binding: url("chrome://global/content/bindings/menu.xml#menu-iconic") !important;
list-style-image: url('data:image/png;base64,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') !important;
padding-left: 4px !important;
}
#openwith-contextsubmenu>.menu-iconic-text,
#openwith-contextlinksubmenu>.menu-iconic-text {
margin-left: 11px !important
}
Since Firefox's page/link context menu is dynamic, I'd like to be able to locate the Open With/Open Link With sub-menu more quickly by having the option to add Open With's own icon to the left of its context sub-menu.