Indeed, the level of customization in Vivaldi is awesome and what Firefox should've done instead of going the other way (that would counter the lame excuse you

Indeed, the level of customization in Vivaldi is awesome and what Firefox should've done instead of going the other way (that would counter the lame excuse you link to elsewhere that "view image" makes the menu too long - just make the menu editable, duh!), even though their UI is unfortunately not very petformant