toolbar button transparency issues Puntuado con 3 de 5 estrellas

although not on all machines, a number I have this on are having problems where mousing over a toolbar button makes the button become partially transparent in big random square blotches. If I mouse on and off of ot again enough times, it may randomly become fully opaque again. What is causing this? Can I repair it manually in the userchrome settings?

Esta valoración es de una versión anterior del complemento (21.1).  Este usuario tiene 7 valoraciones anteriores de este complemento.