New mail icon missing for TB15 Rated 5 out of 5 stars

This is an excellent extension.

It used to work for TB14 on my WindowsXP-SP3. However, the new mail icon (an envelope over the TB icon) in system tray does not occur any longer.
I do have a popup new mail notification.
Any idea?

This review is for a previous version of the add-on (1.0.1).