ArcGIS Pro 2.5 - Measure tool graphic options, etc

[KeithAddison2]

How do I get rid of this white buffer it automatically shows?  It obscures what I'm trying to measure.  What is its purpose anyway?  Where are the graphic options for changing the line's thickness, color, etc.  Also how to I get the distance measure to stop drawing isolines (or whatever their purpose is) on the fly automatically, they slow it down to the point where the causes incorrect clicks that tank the entire measure operation and I have to start over.