Small improvements in drawing module

[wieszak]

I lately work a little with this module, and few rather small things just annoyed me much. I know that is development and etc, but maybe this could be easily fixed: After adding some part to drawing i got toolbar with selection of view, scale, position and so on. When part is somewhat complicated then update process starting to be quite long. Ok, let it be, i understand that this is not trivial to do it, i only want to not doing unnecessary updates: when i just press tab on some value in position / second position without changing the value of it could skip update - and save some time. And maybe add button 'update' ? So i could change positions/deltas (sometimes i now how to change few of them without checking result, so i dont want to wait after each change) then press update to recalculate.

And second i think small change - if i change scale, maybe deltas to secondary views should also be changed accordingly ? Or checkbox if do this or not?