Comment 11 for bug 1806256

Here is some information which may help to reproduce my problem. I have not installed Firefox via Synaptic but instead downloaded it via the mozilla page. I only had to extract the compressed file and then launch the executable. So my Firefox is installed under /home/myname/bin/firefox-release/. Then I created a .desktop file under /home/myname/.local/share/applications/ and set the icon name to "firefox quantum". This icon can be found under /home/myname/.local/share/icons/hicolor/128x128/apps/ and has a width and height of 128 pixels.