Shift-cllick + drag to move many stacks

[Honktown]

Simple: sometimes I have to move lots of material, but I want to put it in more than one place. Currently you can move 1 stack at a time by shift-clicking, or move everything with ctrl-click. Shift-click + dragging wouldn't interfere with any existing actions, and it would let me move one stack, and as long as I hold down shift, I could drag over any other stacks of the same thing and move those too. Right now I have to click all the stacks individually.