Currently when running Firefox ESR under Debian Linux version 12.9.0 with the amd64 architecture. With the Mate desktop environment installed, a non private mode maximised browser window doesn’t show restore down icon. The button for restore down is completely blank with no icon, the caption “Restore Down” still appears. Additionally clicking on it will still perform the restore down action, as well as you can see that the button is high lighting. Also without the high lighted icon or the icon with its highlighting effect.
It’s when running the initial theme and appearance which is installed with the Mate desktop environment.
Can this please be fixed by adding the missing icon, or appropriate resources?