Hello VanKurt and welcome to the ArtRage forums 
Opacity for individual layers can be set on screen via the Opacity icon in the bottom left corner of any given layer.
Click hold on it and drag down or up to change opacity.
Hovering the cursor over the icon will show it’s current opacity %.
Unfortunately adjusting opacity for a layer Group dose require typing in a number still.
Regarding tooltip pop-ups, like the Opacity % mentioned above, you can go into AR’s Preferences > Interface > Tooltip Delay and set it all the way over to the left if you want them to show more rapidly.
Maker Of Replica Macoys
Techie Stuff:
ArtRage 6.1.1 ~ 15" Macbook Pro ~ macOS 10.14.6 ~ 4 Core i7 3.1GHz CPU ~ 16GB RAM ~ Wacom Intuos4 M