About this Add-on
This is useful if you want to exclude some recipients from the current message.
Identical contacts in several lists will be displayed once.
TB91 has a built-in facility to expand a mailing list. Right-click on the list and select 'Expand list'. So you probably do not not need this addon.
The addon will expand all lists at once. It will also remove duplicates, so it may be better if, for example, you want to remove a recipient who may be in several lists.