Unwanted stub lines when sketching

When sketching lines, I often get unwanted stub lines in my sketch.  For example, let's say I sketch a simple rectangle. When the four lines of the rectangle are complete and I go to extrude the rectangle it fails.  I will go check out the sketch only to find a small stub line that I inadvertantly had placed in the sketch.  This happens quite frequently with both me and my co-workers.  Is there a setting within SW that I can change to help reduce this?

Thanks,

Brandon

SolidworksSketching