Trim/extend edge mode strange

Have just found the trim and extend to implied lines (edge mode?).For extending lines this is brilliant. But for trimming lines its a disaster when used as trim to all. Select trim and enter and try trimming a line and it will trim to any implied lineintersection in the drawing. This is as useless for extending but usually you do extend to a defined line.This is no bug it works the same in BigBrother2000 (Its to my opinion as useless there)The way it should work is that whenever trim/extend all is selected implied lines should be turned off automaticly.