This check box is located at...
Document Properties/Dimensions/Linear/Text Position
By default it is unchecked.
I believe if the arrows are on the outside of the leader lines it, by checkling this box SW doesn't draw the dimension line between the leader lines.
The problem is it's not working for me. I'm trying to dimension without leader and dimension lines crossing. I know there is the option to break dimension or leader lines but it's not what I want.
Another option is to convert the text in the dimension from horizontal to vertical but I don''t think Solidworks will let you do it.
Enclosed are some jpg's to help explain what I'm after.