'Painting' Fog of War

Is there a way to do a large area selection, you know click-hold down button-drag cursor-create rectangular field-release button, for Fog of War? Or are you restricted to the single shapes that you then need to link together?

I'm looking at a basic interior structure on a map (there is no roof so as is everything is visible). When players enter the first room (2x2) I want to click off that FOW section, then when they enter the next room (4x8) I want to click that one off. But I don't want to have to put down 32 separate square FOW tiles. I know click-n-drag will only let me do rectangular shapes, but I'm okay with that when dealing with large areas, since having so many separate square markers makes it difficult to find things in the FOW chooser.

Honestly having a single button click to turn on/off a particular room, and having that room named something relevant would make things pretty easy - and I can see that that functionality is there. It's just dealing with large sections takes a while to 'paint' and associate individual squares together.

Secondary question, if one has painted the map with FOW via the 'Flood' map function. Is there a way to un-flood the map?

 

Thanks! I'll experiment with this some this week and see what other questions it leads to! Appreciate all the help!