Freron MailMate

I'm building a list of newsletters that I want to tag automatically with "newsletter". I've set up a rule in the "All Mail" mailbox which checks on a condition of "any" for a list of "from" values.
To add a newsletter to that list, I select a copy of the newsletter email and open the rule. I then add a "from" condition to the rule.

When creating a rule from scratch, the "from" value (and, I believe, any selector you chose) is populated with the value of the currently selected email.
However, when adding a condition, this is not the case. It's left blank. I need to change the selector (for example chose "from>name") and the selection is then pulled in. If I change back to the initial choice I now get the right value.

This is suboptimal as it is way too fiddly for everyday, on the fly, usage.

Not sure if it's a bug, though.

thanks!