543631 - Messages worth two in dock icon count

Status: RESOLVED DUPLICATE of bug 516477

(Thunderbird :: General, defect)

Description

[Marianne Gagnon]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.1.7) Gecko/20100111 Thunderbird/3.0.1

On OS X, Thunderbird displays the number of unread mails in the dock icon.
Today I received 5 mails (and had no other unread mail), but the dock icon said "10". I opened the first mail; the count went down to "8"; I opened the second mail; the count went down to "6"; etc... It turned out each of these mails was reported twice in the dock icon

Unfortunately, the problem does not always happen, and I have not identified any way to systematically reproduce it.


Reproducible: Sometimes

Steps to Reproduce:
1. Receive mail
Actual Results:  
The dock icon should reflect the number of messages received

Expected Results:  
The dock icon count is twice what it should be

happened on a IMAP account, but I have no idea if it's related.
I have only one Add-On, which is QuoteCollpase, but I saw erratic dock icon behaviour before installing it.