43WR shutdown problem

I'm not sure if this is a fault, or a 'feature'... When viewing pictures on the camera one at a time, when I get to the last picture and click as if to go to the next one, the camera shuts down. It does the same in the opposite direction. I would expect the camera to either not do anything, as there is no next picture to display, or go back to the beginning, or end, again. But to shut down completely? Struck me as strange. My other cameras don't do it, but they're not Pentax models, so I wondered if it was a fault.