Feature Request: Additive selection on hotkey

[OrangeDecay]

Problem to be solved

One thing i thought of as bizarre in Dream Maker is that you cannot stack selections with each other and thus make a selection shape that isn't a square.

Sugest a solution

To demonstrate, i will use paint.net as an example:

We got our first selection as per usual

Then, we hold a hotkey, and drag drop another selection, merging it with all the previous ones

While holding the same hotkey and rmb drag dropping selection, you remove the turfs you dragged through out of selection

Hopefully i demonstrated the value of having this feature.