[Bf-funboard] Rectangle select (B key)

[Fergal Gribben]

I remember a friend telling me about a 3D application they had used in the
past, and iirc, if you started your rectangle selection from the bottom
left and dragged to the top right, the selection would be added to your
existing selection. If, on the other hand, you dragged from the top right
to the bottom left, the selection would replace your existing selection.
Would something like that be worth implementing?