firefox emoji are black and white

hello,

I am using Ubuntu 19.10.

For Firefox on many websites emoji appear black and white instead of coloured. Same are coloured in Google Chrome.

Here is an example: https://en.wikipedia.org/wiki/List_of_emoticons

Supplemental Images all appear coloured, on Emoticons only 20% are coloured.

This is what appears in Firefox Debugging tools:

Code:Fonts Used DejaVu Sans
DejaVu Sans Bold Oblique

Noto Color Emoji
Noto Color Emoji
The correct fonts are applied to emoji:

Code:fc-match 'EmojiOne'NotoColorEmoji.ttf: "Noto Color Emoji" "Regular"

Code:fc-match 'EmojiOne Color'NotoColorEmoji.ttf: "Noto Color Emoji" "Regular"

However, I think that DejaVu takes precedence over Noto. I tried to change that:

Code:<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<alias>
<family>serif</family>
<prefer>
<family>Noto Color Emoji</family>
</prefer>
</alias>
<alias>
<family>sans-serif</family>
<prefer>
<family>Noto Color Emoji</family>
</prefer>
</alias>
<alias>
<family>monospace</family>
<prefer>
<family>Noto Color Emoji</family>
</prefer>
</alias>

<match target="pattern">
<test name="prgname">
<string>firefox</string>
</test>
<edit name="family" mode="prepend_first">
<string>Noto Color Emoji</string>
</edit>
</match>
</fontconfig>reloaded the fontcache and restarted firefox. It did not solve the problem.

I don't know how to further debug, I don't understand enough about font configurations. I would appreciate some help, thank you!

BTW, Mozilla Thunderbird works perfectly with Emoji! :scratch: