mozextension page theming can break addons

[CharoSW]

I use a sidebar addon which can link into the new firefox theme api. Because the userContent part of firefox-gnome-theme sets the background color of mozextension pages statically that part of the extension breaks. So while this setting may be useful for mozextension pages that show in a normal tab it can have unintended side effects for those that show in the sidebar. Is there possibly a way to restrict the theming to just the normal tab pages

[lunakurame]

I don't think there is a clear way to restrict theming just the settings page but not other pages since the extensions' file names seem to not be standarized, but we can try to hack our way around this problem with a regexp, similarly to how we handle extensions' popups:
@-moz-document regexp("^moz-extension://.+/popup.html$")

Can you give me a link to that extension you are talking about or its name, so I can test if it works with my regexp? I see uMatrix adds a panel to the sidebar too, its URL is moz-extension://<extension id>/logger-ui.html. And it's the same for uBlock.