Imported From: http://groups.google.com/group/in-portal-bugs/browse_thread/thread/6d6784e357199666#
When you have some slow js on the page, like 500 records per page and while
they are being loaded try to open a window like pressing "Add" toolbar
button, then you will get JS error about "TB.imgLoader" being undefined.
Here is the patch to fix that.
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