I have to admit to a bad habit. I don't take the time to properly name my constraints as I create them so when it comes time to start tracking what is constrained I usually have to do some hunting around my assembly. Luckily, Inventor 2010 has made my life a little easier.
Visual Enhancements - When editing constraints the highlight for the selections involved in the constraint have been further clarified as well as the existing color match to selection. Color under Selection 1 matches highlight on the screen and so forth.
Constraint Names - A new application option on the Assembly tab enables the ability to show component names behind the constraint to better find the corresponding part.
Icon Enhancements - a new Mate constraint icon is used for axial aligning of conical or cylindrical surfaces. This does not apply to edges. This new icon is used to help differentiate between Mate types and requires no extra toggles.
Room for improvement - these enhancements have been great but another nice enhancement that I would like to see and does not currently exist is to have the option of naming the actual constraint during creation instead of having to go back to the browser and soft double clicking a rename.
Until next time, may your constraints selections align in the right direction.