Firefox theming

Hello everyone,

Firefox provides some kind of adaption to the GTK3 theme.
Sadly this is sometimes limited and sometimes it takes the css part from the “wrong” place in the code.

Here are some examples:

  • Firefox can’t handle round border edges in its context-menu
    And to cut the round corners and keep them for GTK3, we would have to make some chaos in our code, to divide the Firefox context menu from the gtk context menu.

  • Firefox provides a CSD with its latest stable release (not default but easily accessible and long awaited by many Linux users) - sadly it can’t handle the round edges of GTK3 themes here neither.

  • A way of changing the theme of the whole window is als provided but in opposite to chrome or gtk3 apps Firefox also themes its headerbar with the applied theme, thus our window-decorations are laid upon their background:

  • the colors of selected text are taken up from GtkTextView but from GtkView and GtkView is taken for other views as for example the nautilus main view - so we can’t have individual coloring of the text and the icon selection if we want to keep Firefox color consistent to the rest of the theme

  • the buttons in confirmation dialogues look different to ours (they actually look like gtk2?):

I opened a bug about this here:

@c-lobrano and @godlyranchdressing : So I would suggest to ignore firefox for the selected text and the context-menu issues at the moment and wait for a reaction/solution from Firefox :slight_smile:


@didrocks @jbicha

I noticed that when you install a fresh disco and start firefox in the ubuntu session OR the gnome-session, this border bleed is not visible:


However in communitheme or yaru development sessions it is visible. Is there anything we could do from our sides to prevent this?
Or is that a session variable thing from firefox side?


This is weird, I’m on an updated machine and I can’t reproduce that. However, I’m with the default (meaning, system titlebar) and not CSD. So maybe something upstream hardcoded in CSD depending on session. @oSoMoN any idea?

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This is reproducible with CSD only

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Ah yes, sorry. As @c-lobrano said, you need to un-tick this box:

Then the white border bleed happens with communitheme and Yaru-session but not with default ubuntu-session