When autotracking is enabled, the meridian and coronal dosimetry planes will automatically rotate or translate to pass through the center of the plaque whenever the plaque is moved on the eye. Autotracking is enabled by default.
To move a plaque without changing the 2D dosimetry plane locations, you will have to disable autotracking. As a convenience, PS offers several places where you can enable or disable autotracking.
The Track button in the Setup Window and the Planes Track Plaque Motion item of the Setup Menu and in the Plane Location Window all enable or disable autotracking.