Hmm in that case you can put your content in a standard, clipping square box, with a bit of padding, then wrap the thing in an overlaybox, and add a rounded border on top with only an outline that covers the borders :
Hmm in that case you can put your content in a standard, clipping square box, with a bit of padding, then wrap the thing in an overlaybox, and add a rounded border on top with only an outline that covers the borders :