Problem is 99% solved by doing the following: explicitelly added element convertor as Pete sugessted: <h:selectManyListbox id="theList" value="#{testAction.multiSelect}" > | <s:selectItems value="#{testAction.allElements}" var="element" label="#{element.name}" /> | <f:converter converterId="elementConvertor" /> | </h:selectManyListbox> In param tag I called a convertor for the list parameter: <?xml version="1.0" encoding="UTF-8"?> | <page xmlns="http://jboss.com/products/seam/pages" | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | xsi:schemaLocation="http://jboss.com/products/seam/pages http://jboss.com/products/seam/pages-2.0.xsd"> | <param name="theList" converterId="elementListConvertor" value="#{testAction.multiSelect}" /> | </page> The convertor is implemented as below: | @org.jboss.seam.annotations.faces.Converter | @Name("elementListConvertor") | public class ElementListParameterConvertor implements Converter, Serializable { | @In | private EntityManager entityManager; | | @Transactional | public Object getAsObject(FacesContext context, UIComponent component, String value) { | if (value != null) { | String[] allIds = value.split(" "); | List<Element> theList = new ArrayList<Element>(); | for (int i = 0; i < allIds.length; i++) { | String id = allIds; | if (id == null || id.trim().length() == 0) continue; | theList.add(findElement(id)); | } | return theList; | } | return null; | } | | private Element findElement(String id) { | List<Element> allElements = TestAction.allElements; | for (int i = 0; i < allElements.size(); i++) { | if (allElements.get(i).getId().equals(new Integer(id))) return allElements.get(i); | } | return null; | } | | public String getAsString(FacesContext context, UIComponent component, Object value) { | if (value instanceof List) { | List<Element> theList = (List<Element>) value; | String s = ""; | | for (Iterator iterator = theList.iterator(); iterator.hasNext();) { | if (s.length() != 0) s += " "; | Element element = (Element) iterator.next(); | s += element.id; | | } | return s; | } | return null; | } | | } | Having that done, all works (without need for any conversation propagation and so on). Also if you call in the browser "localhost:8080/test/xList.seam?theList=1%202" the entries in "select" are selected as expected. The single point that does not work is the url when you submit the page: - point the browser to "localhost:8080/test/xList.seam?theList=1%202" - system shows first two entries in list selected (AS EXPECTED) - select the third entry and press submit - system update the browser location to "localhost:8080/test/xList.seam" (WRONG, the correct is localhost:8080/test/xList.seam?theList=1%202%203) For input Fields and selectOne, the system behaves as expected - parameter is automatically added to the URL. The problem is specific to selectManyListbox component. Additionally, if you have a : <s:link view="/xList.xhtml" | value="Test List" | propagation="none"/> the select multi parameter is not automatically added (while an input filed and selectOne is). Thanx again to Pete Muir for give me the valuable hints. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4105957#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...