Thunderbird spam

[Keith Powell]

Regularly, when I download my mailing list headers, they are *all* 
marked as spam. I've then got to unmark them all, except for those which 
I know are spam, which is rather a nuisance - especially if it is the 
150+ overnight headers!

This happens with Thunderbird on other distros as well as Ubuntu, and 
with several versions of the program.

When downloading, I have made certain that my mouse pointer is well away 
from the "spam" column, in case that is triggering it.

Is there a way of solving this problem, please, or is it an on-going bug 
in Thunderbird?

Many thanks for any advice.

Keith