Not possible to change image or edit crop

hi,

I'm not quite sure of the etiquette, as I realise the 6 release is an alpha so perhaps I shouldn't be reporting this - sorry if I'm wrong to.

I upload an image using imagefield, crop it and save the node.
I then try and Edit the node to change the image.

If the field does is not contained within a fieldgroup:
I can see the original image.
I can see the cropped image.
I can see the cropping tool over the original image.
I can't see the upload form to upload a new image.

Even if I move the cropping tool so it shows a different preview below, when I press SAVE node the crop seems not to have taken affect. (NB: if I then go back into the Edit form the crop remembers it's new position over the original image)
Because the upload form is not there, I cannot upload a new image in it's place either.

If the field is within a fieldgroup with fieldgroup style set to always open
Exactly the same situation as above

If the field is within a fieldgroup with fieldgroup style set to collapsed or collapsible
I can see the original image
I can see the cropped image
I cannot see the cropping tool over the original image
I cannot see the upload form to upload a new image

If the field is within a fieldgroup with fieldgroup style set to tabs (using CCK Fieldgroup Tabs)
I cannot see the original image
I can see the cropped image
I cannot see the cropping tool
I cannot see the upload form

I tried disabling CCK Fieldgroup Tabs to see if that was the issue. The same problems occurred with it disabled.

I hope this might help point you in the direction of the issue.

Thank you

Thomas