When I click the Working Set dropdown in the client, I want to be able to toggle on/off respective Working Sets easier.
At the moment, if I'm in one Working Set, to SWITCH to another Working Set, I have to click the dropdown, tick the new Working Set to show it. The dropdown then automatically hides, I have to choose it again, and then tick to hide the old Working Set I no longer want displayed.
I always SWITCH and never show multiple sets - the designer client becomes slower the more Working Sets I display.
So I would propose clicking to show the Working Set dropdown, then clicking to hide it myself, manually (so it doesn't auto-hide) or a "submit" to hide it.