webuijsf:listbox multiple option not working

Hello, JSF gurus,

I tried to use webuijsf:listbox for a multiple select dropdown list. Bu the result list does NOT have a scroll bar even if I have more items than specified in 'rows'. I've been searching on web for a while for this but it seems everyone is using it with 'multiple='false''. It does not matter I used 'selected' (with backing as an array of String or Object). The scroll never shows up




JSP code
<webuijsf:listbox disabled="false" multiple="true" rows="1" id="test2" items="#{queryBean.allPlatforms}" />

Java Bean code
public Option[] getAllPlatforms() {
List<Option> tmpPlatforms = new ArrayList<Option>();

tmpPlatforms.add( new Option("t1", "t1") );
tmpPlatforms.add( new Option("t2", "t2") );
tmpPlatforms.add( new Option("t3", "t3") );

allPlatforms = tmpPlatforms.toArray(new Option[1]);

return allPlatforms;
}

public void setAllPlatforms(Option[] allPlatforms) {
this.allPlatforms = allPlatforms;
}

if I remove 'multiple="true"', then the scroll bar shows up. And when I put 'multiple="true"' back in, the scroll bar is just gone. Seems to me no one has tried this option with listbox before.

Please help. Feeling so desperate. What a headache! Thank you very much in advance