Hi Thomas,
I’m trying to understand the situation in which an application would need to add the “org.nspasteboard.source” marker, but would not know what the source actually was. That is, the naïve and obvious solution seems to be: “if the source is not known, do not add a ‘org.nspasteboard.source’ marker.”
The only scenario that occurs to me is something along the lines of restoring the pasteboard to its previous contents after performing some kind of pasteboard manipulation. But even then, if the original source of the data being “restored” is not known, just not including “org.nspasteboard.source” seems reasonable. I guess maybe you are worried that some other application, upon “seeing” pasteboard content has been updated, might assume that your application was the “source” of the un-marked content?
That is, it’s difficult to document a use case that I don’t understand.