Problem with assign ing 'global' action to multiple layers

Mac version does not allow me for changing layer colour, print thickness or even switching on and off on multiple layer at once. Everything needs to be repeated on-by-one.
This is essential functionality, please make it happen (unless there is something wrong with my version).
PS I’m running lates updates.

The layer manager in Rhino 5 for Mac is deficient in this way. What we need is a complete rewrite of the layer manager to work cross-platform. This is a huge task that @dale is trying to get himself psyched up for…it’s a big task.

I know this is not the answer you are looking for, but there is nothing wrong with your particular copy of Rhino 5 for Mac; it is a general problem.