The icons/buttons in the effects/composition stack in new Kdenlive Version 21.12.3 appimage are to dark to read. I'm using Linux Mint 20.3. For example enable keyframes button, go to next keyframe buttons, any that are dark. Only using Breeze, Breeze light or Default Color Theme, which have light interface backgrounds do the buttons show up adequately. I prefer using a dark user interface to work with to save my eyes. I've tried Rusted Bronze and the buttons show up just enough to work with. Is there something to change this so the buttons invert to light icons or inverted to light and readable as the previous Kdenlive 21.12.2. Appreciate any help. Or a mention to the developers.

Just found the answer on Kdenlive Manual Troubleshooting:

install frei0r-plugins and breeze-icon-theme or breeze-icons from package manager
Also in Kdenlive Settings tick Force Breeze Icon Theme

After that all good.