Diffs are not colored when using the Thunderbird Conversations add-on

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Install Thunderbird Conversations add-on 
(https://addons.mozilla.org/en-US/thunderbird/addon/gmail-conversation-view/)
2. Open a message with a diff in conversation view

What is the expected behavior? What do you see instead?

The text inside the conversation view remains as plain text

What version of the product are you using? On what operating system?

colored diffs: 0.6.2011.11.22.17.42.09
Thunderbird: 11.0.1
Thunderbird Conversations: 2.3.2

Please provide any additional information below.

Turning off the conversation view and view the message normally results in the 
colored diff showing.

Original issue reported on code.google.com by [email protected] on 30 Mar 2012 at 7:57

[GoogleCodeExporter]

Same problem here

Original comment by [email protected] on 20 May 2012 at 6:40