In the current state, onPortalMove will trigger PortalLayout service() method to move the panel according to user action.

This is fine if using the component in a MVC pattern, but it makes using a MVVM / template approach difficult.

In order to control the component directly, we would need a way to stop onPortalMove propagation in a listener before portalLayout changes its own content.

This would enable patterns such as:

<portallayout>
 <portalchildren>
  <forEach items="@load(vm.tasks)">
   <apply templateURI="kanbanpanel.zul" item="${each}" />
  </forEach>
 </portalchildren>