We have found that older versions of the Firefox browser can have a problem when attempting to select a custom header or gallery image on the listing page. The browser becomes unresponsive and eventually displays a message box saying "This script is causing Firefox to run slowly...".
We have not had this problem with the latest version of Firefox (1.5.0.4) or Internet Explorer. If you are experiencing this issue with to the latest version of Firefox, please file a support case.
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