I’d like to give that inital wish a bump:
When I double-click a level in the panel (all level light bulbs are on), the levels below are kept on, too, and only all levels above are turned off.
This is usually not what I want - I’d like to work on a single level most of the time. Result is, a felt 100 times a day I need to turn off the lightbulbs below the desired layer. (Starting from the bottom, because if I try to turn off the level below the desired level, the desired level is turned off instead.)
So, the logic behind the Level panel’s on/off column is… strange and impractical.
Would it be really such a difficult fix to make it work like this:
Double click a level, and this level ONLY is left on! It’s easy then to switch on levels above or below by turning on the top- or bottommost level, so there’s not much to change.