When changing the Product Value on an existing bug the Version and Component
selects are not repopulated with values appropriate for that Product.
Specifically this affects #145253, which I would like to change to Fedora
Bugzilla doesnt assume that the components and versions match from one product
to the next and forces the user to select the new component and version. This is
by design in line with the upstream version. Please file this bug at
http://bugzilla.mozilla.org against their Bugzilla product as this may end up
being a good feature to have.