There are new icons on Plasma last version for OSD when you hit fn+display (I think it is since january 2018). Once installed they are located here /usr/share/icons/breeze/applets/64 and they are named like osd*
See how it looks with breeze:
I am a big fan of Numix-Square, so I did not want to switch back to breeze just for that.
Here is how I fixed it:
in /usr/share/icons/Numix-Square/index.theme
I just added:
There are new icons on Plasma last version for OSD when you hit fn+display (I think it is since january 2018). Once installed they are located here /usr/share/icons/breeze/applets/64 and they are named like osd*
See how it looks with breeze:
I am a big fan of Numix-Square, so I did not want to switch back to breeze just for that.
Here is how I fixed it:
in /usr/share/icons/Numix-Square/index.theme I just added:
Inherits=Numix,breeze
instead ofInherits=Numix