Maintaining relative axis directions using the Plane Normal tool

I have had a lot of trouble using the Plane Normal tool lately.  My central problem is that if the direction of the z-axis vector used to define the normal of the plane changes, the x and y axes will suddenly exchange. Is there anyway to lock their relative directions with respect to the z axis (the plane's normal vector)? 

For example, if the vector which defines the plane normal is hinged at its origin, the x and y axes will fluctuate as extreme changes in the vector's direction occur.

Has anyone else had a problem with this?  Is there any sort of quick fix or best practice to employ to avoid this problem?

I think this problem is also experienced while using the perpendicular frames tool.

I am using version 0.6.0057

Thanks in advance!

~Peter