I come from a long history of using SW (since '95) but after the disaster of 2005 I discontinued my maintenance. Today I'm back for 2010.
So anyway, it used to be I could make one line in a sketch equal to any edge on the model. This is no longer possible. Seems that any time the item in question is not parallel to the item I'm trying to relate to is when it fails.
For example, let's say I have a sketch line that I want to make equal to an edge in the model or a line previous sketch (higher in the FMT.) Select both items and all relations are unavailable. I should have several options available, equal, colinear, perpendicular, parallel and what not. Nothing is available.
In fact I should even be able to do this inside an assembly from one part to another. NOT.
I have confirmed that this worked just fine in prior versions.