Still looking for an answer.
Changing or reassigning to the filter\'s innerHTML
successfully redraws the element, but breaks my script, so that\'s out.
Building off of other comments and answers in this thread, I resolved this problem using the Prototype library:
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$("dynamically-added-block").up().show();
Simply, get the parent and re-show it. Tested in IE8, using both Browser Mode: IE8, Document Mode: IE8 and Browser Mode: IE7, Document Mode: IE7. Have not tested with the dreaded quirks mode.