Chamfer feature problem with distance - distance option

I couldn't find this issue after an admittedly short search of the forums, but here it is:

I have run into an issue using the chamfer command.  For whatever reason, every once in a while, the distance-distance option will not function correctly.  When I select that option, normally, 2 dimension boxes open up allowing me to define the distance of each leg of the chamfer.  This morning, when I selected this option, only a single dimension box opened, allowing me only to do an "equal distance" dimension.  What's also strange is that the "Equal distance" check box is greyed out.  Even the on-screen distance boxes won't let me enter different values for each leg.  Is this a common occurance, or is there some obscure setting somewhere that I accidentally toggled.  See attached pic.   Anybody else run into this?  What was your solution?  The only "fix" that corrects this that I have found is to restart Solidworks, which is a B.S. solution at best. 

I am on Solidworks 2011 SP0, but I have encountered this error off and on for the last several years.  And please don't comment if all your going to say is "why do you want to do that?"  My preemptive answer to that is: "because I want to."  I am not asking for advice on modelling techniques, just wondering if anyone else has found out what is causing this issue, and if there is a solution other than a restart to correct it.

Thanks!

SolidworksParts And Features