Dia dim about center line not functioning?

Hello;

     All of suddent it seems I can't do a diameter dim, around the center line, by picking the center line, &

then pulling the dimension to the other side. It doesn't give the diameter option, I just get

the half diameter dim form center to edge. Does anyone know if there's a setting for this,

or what I might have missed.

Thanks, in advance;

Rob_D SW 2013 sp2

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