Version: SeeMusic 5.5.8, Windows 11 Home 22H2 (OS Build 22621.2428)Bar Line and Octave Guide Opacity simply changes from white to black when sliding from 100 down to 0 (instead of increasing transparency, like it used to be). Please fix this.
This should now be fixed in Version 5.5.9
It's available for Windows now from seemusicapp.com