[Zope] manage_changeProperties doesn't for my zclass

[Anthony Baxter]

>>> "Kevin Dangoor" wrote
>    <dtml-call "manage_changeProperties({
>       'firstname' : REQUEST['firstname'],
>       'lastname'  : REQUEST['lastname']
>       })">

An aside here - an easy easy error to miss is to use manage_changeProperties
when you in fact mean manage_editProperties. The former will set all 
properties in a sheet, so that if you don't specify something, it gets
cleared. 

Anthony, who's been bitten by this one too often.