This limitation will bite us in the future if we'll have multiple bgs for the very same location depending on the time (morning/day/evening/night).
It's totally wrong to call this a "limitation" in any sense of form. As I've said, you can specify background when you call the GM, it's a major convenience... not a limitation. Not mentioning that if in some ridiculously improbable scenario where we add times of day, we will prolly still use generalizations like this by adding appendixes to image names and using color masks if there are none (once again, with a possibility to specify exceptions).
Ohhkey, as long as it works just like a normal matrix but with one or more randomly placed areas, it's fine by me.
I don't need it for a normal matrix.
Oki, then it's prolly done, just untested.
Well... I want to use it to randomly hide items and events. It means that after you found an item or an event, the area should no longer be there at least until the next day.
Ideally, it should be under control. When we need to randomize random matrix anew, we do so. When we don't, we don't.
You prolly want to condition this yourself... I am going to leave as much freedom as possible and recode the screen to take more args just so positions could be randomized outside of it.