Thunderbird on Ubuntu

I have been having just a wretched time with Thunderbird on Ubuntu Linux 9.10 the last few months. Thunderbird would regularly peg an 100% of one of my CPUs. Today, to address this, I tried using swiftdove, which supposedly has better performance. I had exactly the same problem, if not worse.
Don't know why I didn't think of this before, but I started to look at the plugins I am using. I have been using Lightning, Tag Toolbar, and MailTweaks. I turned them all off, no more 100%. I turned them on one by one, and found the culprit in Lightning. For reference, I was using lightning 1.0b1. We'll see if sunbird behaves better on its own.
Further investigation shows my big problem is with Remember The Milk. I ended up with the same problems when I ran Sunbird, and subscribed to my RTM tasks. Once I unsubscribed, both in Sunbird and in Thunderbird Lightning, the excessive CPU utilization cleared up.
It would appear that someone isn't testing on Linux, because I don't have these issues on Windows XP.