Without the button background, it's difficult to realize that it's a button.
this should be :
backgroundColor: containsMouse? colorizerManager.buttonHoverColor : "transparent"
and how does it look when the button in activated ?
Hey @trmdi rooty's not participating in KDE at this point so he won't be able to do the review.
Just so I don't stop by without giving a contribution: I like the idea of making it more obvious that it's a button. Maybe you could reach a compromise here and have the background at quite a low opacity when not hovered over, perhaps have this sort of an effect: https://youtu.be/hR_AV1bCS5g?t=12