I understand that Dropbox does not store NTFS Alternate Data Streams (ADS), and I'm not asking to change that. I wouldn't expect to have ADS restored on locally deleted files (unless they're in the recycle bin with ADS intact), nor for them to be recreated when fetching new files from Dropbox servers, though it would be nice.
However, I expect ADS not to be deleted on an exisitng file when it gets an update from another user/device, including renames. It appears as though local files are replaced entirely, rather than just their name, contents, and modified date. This would be okay if any ADS were first copied to the new version, but my tests show they aren't. Can you please correct this bug.
The tool Streams by Mark Russinovich may be an easy way to manipulate that data.