When I am in a drawing and trying to dimension, add notes or balloons, edges from parts behind what I'm dimenion to are showing up and making it difficult for me to be accurate unless I zoom in really tight to select the edge that I need.  I have attached an image to show the issue I'm having.  The lines that are red are edges behind a top panel that I am trying to dimension.  The red lines are coming up when I move my mouse over the assembly.  I also have this problem when trying to dimension or add a note/balloon to a sheet metal part.  It keeps wanting to select a tangent line on the inside of the part or the inner surface edge unless I zoom in tight to make sure I get the correct edge.  Is there a setting somewhere that I need to check?  I haven't been able to find anyting.