TL;DR
Lock moving of blueprints only on vertical or horizontal axis with modifier key.What ?
Aligning blueprints can sometimes be difficult especially on big screens. It would be much easier if normal drawing program functionality: locking direction is implemented.f.ex. if I want to copy something and want it to be exactly same vertical position but move it only horizontally I can select what I want, press and hold modifier key and now direction where my mouse first moves is locked and I cannot accidentally move blueprint vertically.