In XP SP2 and PM 4.5.3, in the IPTC stationary pad - if I click on the "variable" button, the box pops up and works fine. If, however, I move to another IPTC field and try to do it again, nothing happens. I have to get out of the stationary pad and back in to do more than one at a time.
Doesn't happen on my MBP (10.4.10).
Nothing earth shattering but reproduceable.
RG