Message filtering

[pbiss]

seamonkey 2.49 on Windoze.

On my mail server I run the SpamHalter daemon by Lukas Gebauer.
This provides for Whitelisting.
The daemon always places the following header tags:

X-SPAMWALL: Passed through antiSPAM test by blah-blah
X-SPAMWALL: probability - x.x%

and, for whitelisted senders, adds
X-SPAMWALL: Whitelisted

In the configuration of the daemon I can substitute what I like for X-SPAMWALL
but only once, i.e. all occurrences are still the same.
I can also change the "probability" and "Whitelisted" arguments.
(It would obviously be nice to be able to create a [X-SHWhitelisted: yes] header tag.)

To finish off filtering my inbox in Thunderbird, I configured:

Filter name: White
Apply when:
Manually Run
Getting New Mail (before Junk classification)
Match all of the following
X-SPAMWALL - doesn't contain - Whitelisted
Move message to Grey on <myAccount>

This persuaded Thunderbird to examine all instances of X-SPAMWALL
and thus pushed everything not whitelisted into the Grey folder.

I can't get SeaMonkey to do the same, instead the filter moves almost everything,
i.e. seems to ignore the wanted instance.

It seems to me reasonable to expect that
Match all of the following
should examine all instances of the following.

Has somebody "corrected" something in adopting this functionality from Thunderbird?