in ALL 3ds Max up v8.0 Shift+LMB click was extremely fast, convinient, intuitive
1. Shift+LMB click on open edge - extrudes the polygon with zero shift.
2. Shift+LMB click on polygon/element - just creates a copy of polygons with zero shift, now to do this I need to use Detach button, and check both "copy to Element" and "copy as Element".
In 3ds Max-es up to 8 this was useful for numeric modeling, and it also much simple to keep in mind just:
Shift+drag = drag a copy
Shift+click = copy in place.
