Touch Zones

The touch zone (TZ) of a UI Shape is where you must click to select the object. When the mouse pointer is near a touch zone, the pointer changes shape and the object can be selected. If the object is invisible or behind another object, its touch zone is null.

The family touch zone (FTZ) of a UI Shape is the union of its touch zone and its children’s family touch zones. Often an object’s FTZ is the same as its TZ if it has no children.