Files: gui/main.h, gui/moving.c, gui/view.c
VRR has several features which react on mouse cursor movement and cause instant recomputations: the transformation tool, the GO Factory moving hanger on which created objects can be hung, Santiago's transformation tool, and the Fifi. The needed computations may be somewhat lengthy and sometimes, when a large complex image with many dependencies has to be recomputed, not all mouse motion events can be processed.
The computations are performed in idle time; if there is not enough time to process all events, the excess events are ignored. However, the mouse button release event is always processed.