TL;DR
While editing blueprints one should be able to right/left click for a rectangular area.What ?
While editing blueprints right click removes things and left click adds them back. Dragging makes the effect follow the mouse.I suggest that when shift is held then dragging would open a rectangle and releasing the right/left mouse button would then affect the whole rectangular area.
Why ?
Editing larger blueprints is a pain. The entities and tiles become smaller and smaller the larger the blueprint and become hard to hit. Removing a section of belt or pipe with drag click often skips a tile because the mouse moves to fast or one doesn't keep a perfect line and hits the tile next to it. With my suggestion one would hold shift and then carefully click and hold on the first belt. Then move the mouse over to the last belt and release. The whole belt segment would then get selected or deselected.Even more useful when including tiles in the blueprint. I frequently want to trim the blueprint removing whole rows or columns of tiles. Doing that on a 400x400 blueprint is a huge pain. With my suggestion it would become trivial to remove 5 rows at the side of a blueprint. Or to remove an inconvenient lake in the blueprint while leaving the waterfill for offshore pumps.
