Clearing the current selection when using the measure tool.

This seems so simple but I can not get the solution I am after in SW 2012.  I use the MEASURE tool often.  To clear the selections you can just select them again.  This does not work well for me.  It usually just adds another selection rather than selecting the item I want deselected.  Or I might be in a large assembly and going back and forth to deselect is a zooming pain.  ESC will do the job but it dumps you out of the Measure and then you have to select it again and start all over.  Picking nothing out in free-space will clear it as well but it will select items that are hidden (not shown) if you are not truly in free-space.  All too often I am so zoomed in on a part that selecting free-space is again a zooming pain.  Is this tool really that cumbersome to use or am I missing something simple here?