Per bug 1014313 comment 36. Array.map(document.querySelectorAll(":not([removable='true'])[cui-areatype]"), (n) => n.id).join(',') on current fx-team, at least, produces the following list of elements: menubar-items tabbrowser-tabs urlbar-container back-button forward-button webrtc-status-button nav-bar-overflow-button PanelUI-button PanelUI-menu-button restore-button I don't know how many of these can be removed outright and how many will need messing about with CSS before we can do that (or whether that means we should even do it).
(In reply to :Gijs Kruitbosch from comment #0) > I don't know how many of these can be removed outright and how many will > need messing about with CSS before we can do that (or whether that means we > should even do it). I looked through <http://mxr.mozilla.org/mozilla-central/search?string=cui-areatype&find=\.css>. I don't think there's any dependency.
Created attachment 8456537 [details] [diff] [review] patch I also removed cui-areatype from updateCombinedWidgetStyle since (1) it's unused and (2) I think it's better to be consistent and only ever set the attribute on the actual customizable widget, rather than expecting extra code to be written for complex widgets in order to set the attribute on some of the nested nodes.