Removing the ``break;`` here will cause the fileDragDataProvider to be instantiated multiple times, which it wouldn't have been before. I'm not sure what the effects of that would be, but if x-moz-file-promise (which handles HTML snapshots, unlike x-moz-file) doesn't work on Linux then the new code should just blocked off for Linux, leaving the x-moz-file-promise for OS X. I can look into this, but not at the moment.