Rated 4 out of 5 stars

Using version 1.1 with Thunderbird 3.1.2 (Hungarian) the content of "Size" column is not decreased when a mail is deleted from a folder. (Nor with v1.0) It is increased, if a mail arrives to a folder. The same situation after restart of TB or re-install of Extra Folder Columns. Could you please check the situation? (Did I make a mistake?) Anyway, very useful add-on, Thanks! (Would be 5 stars if the problem above corrected)

This review is for a previous version of the add-on (1.1). 

Hi Fonyosz, the folder size is determined by Thunderbird not by the extension.

The way Thunderbird works is that, although you delete an email it doesn't actually remove it from the disk file until you compact the folder. This is done for performance reasons and is why the size doesn't decrease straight away.