Rated 5 out of 5 stars

Re DW-Dev's request:
Here's a list of my installed Add-Ons:

2. Deutsches Wörterbuch (alte Rechtschreibung) für die Rechtschreibprüfung in Mozilla-Produkten 0.2
Account Colors 3.2
Adblock Plus 1.1.3
Adblock Plus: Element Hiding Helper 1.0.6
Address Close Button 1.1
AddressBookTab 1.2
Attachment Sizes 1.0
Auto Address Cleaner 1.0.1
Auto Encryption 0.2.1
Auto resize JPEG images for Thunderbird 0.2.0
Auto Zip Attachments 0.6.2 [DISABLED]
Calendar Tweaks 2.0
Change quote and reply format
Clean Subject 0.4.2
Copy Attachment To Clipboard 0.5.1 [DISABLED]
Custom Toolbar Buttons
Folderpane Tools
GDirections 3.1.5 [DISABLED]
Grab and Drag 2.7.6
Image Zoom 0.4.4
Lightning 1.0b1
Mail Merge 1.0.3
Mailbox Alert 0.13.2
Nightly Tester Tools 2.0.3
Provider für Google Kalender 0.6b1
Quote Colors 0.3
Rename Attachment 0.1 [DISABLED]
Restart Thunderbird 1.0
SearchWith 0.4.3
Send Later [DISABLED]
Sender Name 0.4a
Slideshow 1.3
StarMoveContact 1.0
Unselect Message [de] 1.3
Year View 0.3.0b2
Zindus 0.8.13

This review is for a previous version of the add-on (3.2). 

Problem resolved

This relates to a problem reported in a review on 4 March 2010. This problem is fixed in Version 3.3 which works with Thunderbird 3.1.