CVE-2012-3555: Undefined Security Weakness

Opera before 11.65 does not ensure that keyboard sequences are associated with a visible window, which makes it easier for user-assisted remote attackers to conduct cross-site scripting XSS attacks or execute arbitrary code via a crafted web site, related to a "hidden keyboard navigation" issue...

Hidden keyboard navigation can allow cross site scripting or code execution

When a user is interacting with a window, that window should be visible to the user, to ensure that the user realizes it is there. If a page is displayed in a small enough window, the user may not realize it is being displayed, and if the right keyboard sequence is carefully followed, they can en...

Hidden keyboard navigation can allow cross site scripting or code execution – Opera Security Advisories

When a user is interacting with a window, that window should be visible to the user, to ensure that the user realizes it is there. If a page is displayed in a small enough window, the user may not realize it is being displayed, and if the right keyboard sequence is carefully followed, they can en...