Why does ZA Pro's 'Adblocking' under the privacy feature suddenly interfere with the chat function in the new Yahoo! email?

Could somebody please provide some information, guidance or suggestions?

ZA Pro always worked fine with the new Yahoo email (with Cookie Control and Mobile Code Control both set to 'off').

However from yesterday the chat function in the new Yahoo email won't load unless the 'Adblocking' feature is set to 'medium'. It hangs on 'Loading Chat' but works fine when the button is set to medium.

Through a process of elimination with the following programs (ie. turning one variable off at a time - Noscript, Zonealarm's privacy features and Adblock Plus) it was determined that ZA Pro's Adblocking feature in 'Privacy' was unfortunately the culprit!

ZoneAlarm Pro 8.0.059
Firefox 3.0.4
Adblock Plus
Noscript 1.8.5

Thanks in advance!