Problem when the element dragged is a message from Outlook about filedrop

[ProgerXP]

Dragging stuff out of an application is tricky and depends on that application. It uses Windows drag & drop mechanism but it has many flavors. For example, sometimes it would create a temporary file so that drag & drop occurs in two phases: (1) source application saves data to a temporary file on disk, (2) destination application reads that file as if it was dropped directly by the user. If it's this case it usually universally works. However, often direct drag & drop is used so that the source app attempts to transfer the file directly to the destination. This is incompatible in many cases but is more optimal in terms of performance (no need for any temporary files and disk IO).

So to sum up: if you're working with the browser it's best to drop files that are already written to disk. This way it will work 100%. If you're dragging a file that's coming from some other app it might work but also might not (actually, it probably won't work).

[andy194]

I've been investigating this too. I've found that browsers expect CF_HDROP but Outlook supplies CFSTR_FILECONTENTS & CFSTR_FILEDESCRIPTOR, which browsers don't understand. The drop event is triggered in js code but there's no data that I can find. Lot's of advice on this out there is that the browser needs a custom plugin, but I believe that Microsoft are removing that option from Edge, preferring the Mozilla script mechanism for extensions.

The thing I'm looking into is that the Google search page does receive information from the drop event from Outlook and displays it.