I am working on a drawing of a simple assembly made of 2 parts. I want to dimension from vertex A to vertex B. I can't select vertex A. When I hover around it with the mouse I can only select the edges nearby, it ignores the vertex. I am able to select vertex C. I don't understand why I would be able to select it but not A... If I turn on the 'Vertex' selection filter by itself, I can pick A.

I recently upgraded from SW2013 to 2015. I don't remember having this issue before.

Any ideas?