Is there any poosibility to set how much items has to show and only show a scroll bar when there are more items in the list?The scrollbar for a poplist is handled by Forms internally based on the number of items in the list. There is no way to directly control the scrollbar. You may be able to control the scrollbar if you create your own Pluggable Java Component (PJC). PJCs are discussed in the Help documentation.
Or other way: set the maximum of shown items so big, that there will be no scroll bar.I don't think so, but you can try it.