Hi again!!
 
When I am in sketch mode, and want to make a circle tangent to another, I simply click once for center, then drag the circle to the surface of the other circle, and bam! tangent constraint.
 
That 'auto-constrain' feature seems to not work anymore.
 
Why would this happen?
What setting will turn it back on?
 
Any suggestions?

never mind that one, lol.
its apperently a setting called 'constaint inference' within the 'constrain' ribbon.

Try the following:

1.Click right button on Sketch
2. Select Constraint Options
3. Check which contraints you want activate.
4. Click OK