sorry, the description is not enough, but I'll try to explain.

using pro version 1.2 (latest version)
on this URL
socvest.dk/content/view/95/49/

in IE, all is well,
in Firefox, browsing the menu item "første maj 2007" first time everything is ok, when clicking on the menu item again more than half the time the images are not 3 on every line, but maybe 3, 1, 3, 2, 2, etc.

The page validates, so this is not (ít seems to me) a programming issue.

Someone have a good idea what to do to get this to work in Firefox ???

Thanks in advance for your kind help !