Thunderbird Hang high CPU

[leona]

Hi
I've installed Ubuntu 12.04 recently, using Gnome classic not Unity.

I have an issue with Thunderbird (currently version 17) when I scroll through emails or select them to view the application hangs.
I see 'Thunderbird' and 'dbus-deamon' listed in 'processes' using 40-50% of the cpu, thunderbird goes 'dark' and I'm unable to click on anything until it releases about 10-20 seconds later.
I could put up with this for a while, but its really annoying now.
I've disabled all plug-in's thinking it was that.
Any ideas?
Thanks.

[leona]

I have tried these ideas but to no avail :(
http://superuser.com/questions/60319/why-would-thunderbird-regularly-hang-for-10-seconds

[leona]

Still not any further with this.

[SeijiSensei]

How much memory and how much swap do you have? How large are your mailboxes?

[leona]

Thank you for taking the time to reply to me.
I have 4Gb of Ram, 9Gb swap (0% used).
Arr, yes mailbox size, well that's a little big, I don't like to delete emails (except junk and spam) so its about 4.2Gb, but that didn't seem to be a problem with 10.04