Hi Dries,
try this:
change the lines ~332-335. in system.css:
from
/* Avoid jumping around due to margins collapsing into collapsible fieldset border */
html.js fieldset.collapsible .fieldset-wrapper {
overflow: auto;
}
to
/* Avoid jumping around due to margins collapsing into collapsible fieldset border */
html.js fieldset.collapsible .fieldset-wrapper {
overflow-y: hidden !important;
}
Best,
Tibor
ps.: sorry, but I'm not @ my computer at the moment so I can't provide a patch. At first sight it works for me, it eliminates the vertical scrollbar in FF.