Green Axis showing through - a bug or me?

Is this a bug or my system? When I draw a face or double face solid at a distance from the axis (over 800’ in the attached files), the green axis line shows through the face. Not so close to the axis.
Green Axis Showing.skp (179.4 KB)

Looks like a typical OpenGL graphics thing when the model is at a long distance from the origin.