Opera offers an Open button to verify that a user wishes to execute a downloaded file, which allows user-assisted remote attackers to construct a race condition that tricks a user into clicking Open via a request for a different mouse or keyboard action very shortly before the Open dialog appears. NOTE: this is a different issue than CVE-2005-2407.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2004-2649
http://www.squarefree.com/2004/07/01/race-conditions-in-security-dialogs/
http://archives.neohapsis.com/archives/fulldisclosure/2004-07/0264.html