Please bare with me as I am coming from 2006 directly to 2013.

I noticed that while I have a part up I used to be able to put some dimensions on it. This seems to not be the case in SW2013.  It has done it a couple times, but for the most part it does not.

For example, if I create a simple cylinder, I can dimension the top and bottom surfaces for the overall height, but can't pull a diameter dimension off of either the top or bottom edge. 

Is there something I am missing?? 

Thanks in advance,

Tim