Probe direction

I usually have to rotate the "Z" axis on my models to measure the opposite side of the part. I go to alignment, rotate Z 180 degrees about X or Y and my trihedron shows the correct Z direction.
My problem is with the direction of the stylus, it does not rotate with the new alignment. I do an F5 and check to see if the probe is facing Z minus and it is but the screen still shows the probe facing the Z plus direction.
What am I doing wrong.

Thanks!!