Mozilla developers David Chan and Gijs Kruitbosch reported that it is possible to create a drag and drop event in web content which mimics the behavior of a chrome customization event. This can occur when a user is customizing a page or panel. This results in a limited ability to move UI icons within the visible window but does not otherwise affect customization or window content. External Reference: http://www.mozilla.org/security/announce/2014/mfsa2014-60.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges David Chan and Gijs Kruitbosch as the original reporter. Statement: This issue does not affect the version of thunderbird as shipped with Red Hat Enterprise Linux 5 and 6, or the version of firefox as shipped with Red Hat Enterprise Linux 5, 6, and 7.