Stretch detection?

[incans]

One question.

On-

1. load source
   
2. search for a scene where a square or round object is shown that allows me to see the effect of different aspect ratios
   
3. adjust the input PAR (=pixel aspect ratio) so that the observed object looks proper. (testing the standard PARs is usually a good start)
   
4. crop the content (= remove all black bars); this does now change the pixel aspect ratio.
   

If I follow this process, at step 3, with input PAR set but no crop applied, the input PAR setting is not applied to the preview. For example i'm looking at a DVD of Near Dark (1987) which has a 1.89:1 (non letterboxed) stated PAR.

Hybrid calculated a default input PAR of 256x135, which is 1.89:1, but if I preview that with crop disabled I see the 5:4 aspect ratio of the 720x576 data, so the picture is squashed laterally.

If I enable Picture Crop and Crop View, even without actually setting any non-zero crop values, all of a sudden the preview is the correct aspect ratio. Is this the expected behaviour?