Ok, uploading a new release a day after the previous one is uncommon. This smells like a blocking issue fixed...
In fact, the new Dialog implementation had issues with IE when using 8.5.2, mostly because of the way partial refresh is done. I reverted to the old implementation while keeping the new hierarchy/properties, to prepare to the future. This might have to wait for the next release of Notes/Domino. Anyway, the keepComponent property is in as well as the events (onShow, onHide...). But, as shown in the demo DB, the events don't work with the regular event handlers. You should use the client side properties instead.
Apologize for the inconvenience, but as I said earlier, the Dialog control is a really, really complex one...