This is a small bug in alias, but very irritating too. I frequently use align tool, mostly to project align the surface on to another surface, which creates a COS, but then i want to extend that COS for some multiple reason , it doesn't extend. Every time i have to delete the COS and project a new COS using project normal and then i extend the COS, this eventually solves my problem but i end up loosing time plus its irritating too.