Often it's difficult determine what needs to be done to fully constrain a sketch when you're almost there.
Other s/w I've used had a "Show Free DOF" (degrees of freedom) function that would animate the unconstrained DOF, which was very helpful.
For example, if a line lacked an angular constraint, it would rotate, and if it also lacked a linear dimension it would then translate or change length in an oscillating fashion.
This would be extremely helpful.
