Prevent default browser behavior with Plupload disallowed file extensions
|Reported by:||nacin||Owned by:|
See #22149. When Plupload is set to accept only certain file types, the drag event falls back to the browser's default behavior. That means HTML files replace the entire viewport, ZIP files get re-downloaded, etc. Ideally, our own handlers intercept such a drag event and prevents anything else from happening.