Thread hangs trying to use MoveChildComponentChange to implement drag-n-dro

Question

System: JDeveloper 11.1.1.3 Browser: FF 3.6.6
So I'm trying to implement a drop-n-drop between two components, allowing the user to drag elements between on parent component and another parent component:
I never make it past the commonComponentParent = moveChildComponentChange.add(..) line as the thread hangs (during debugging i dont get an exception it just hangs!!), but the reason that I'm getting this, i think, is because the system is giving a null ChangeManager (cm). Why is the RequestContext giving me a null cm when I so nicely asked it for a valid one?
<af:panelGroupLayout id="pgl1" styleClass="appdock appMenu" layout="horizontal" inlineStyle="margin-left: 0px;">
<af:dropTarget dropListener="#{menuComponent.handleExternalContainerDrag}" actions="MOVE">
<af:dataFlavor flavorClass="javax.faces.component.UIComponent" />
</af:dropTarget>
<tr:outputText value="drop here" />
</af:panelGroupLayout>
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import oracle.adf.view.rich.context.AdfFacesContext;
import oracle.adf.view.rich.datatransfer.DataFlavor;
import oracle.adf.view.rich.datatransfer.Transferable;
import oracle.adf.view.rich.dnd.DnDAction;
import oracle.adf.view.rich.event.DropEvent;
import org.apache.myfaces.trinidad.change.ChangeManager;
import org.apache.myfaces.trinidad.change.MoveChildComponentChange;
import org.apache.myfaces.trinidad.context.RequestContext;
public class MenuComponent {
public DnDAction handleExternalContainerDrag(DropEvent dropEvent){
ChangeManager cm = null;
cm = RequestContext.getCurrentInstance().getChangeManager();
UIComponent commonComponentParent = null;
try {
commonComponentParent = moveChildComponentChange.add(fctx, cm);
moveChildComponentChange.changeComponent(commonComponentParent);
AdfFacesContext adfFacesCtx = AdfFacesContext.getCurrentInstance();
adfFacesCtx.addPartialTarget(commonComponentParent);
} catch (Exception e){
e.printStackTrace();
-Rob

Answer 1

Hi,
did you enable change persistence in the ViewLayer project ? The book you have the sample code from mentions this on page 447 "Enabling Change Persistence in ADF Faces RC Projects". To enable this, just double click the view layer project and then select "ADF View". The check the checkbox to "Enable User Customization"
Frank