in V7 you can quickly click on the layer lightbulb to deactivate and immediately click again to activate it. i do that to quickly access geometry location etc.
in V8 and V9 that has become a serious nuisance, you dare click too early it will just ignore the click and you dare keep clicking further to have it activated finally. it will just prolong the activation process even more. what i now have to do is wait a moment then click again.. why? no seriously.. please fix that, Rhino 8 is so tiring in so many details.