Hi,
I'm afraid, the SDK docs (C++ and Python) could need some updating to reflect the latest changes done to dialog borders in S26. It seems most flags are pretty useless, now. BORDER_ROUND doesn't seem to do anything anymore, for example.
Of course, I'd prefer to get back the old border behavior, but I'm not naive and think, this could be an options. But at least the changed behavior should be documented.
Cheers,
Andreas