Alfresco Activiti Workflow Form - How to customise object finder control?

How to customise object finder control in workflow form?

Today I have asked to the folder object as selectable in one of the custom workflow form.

By default, the object finder will allow you to select the file only. 
When I looked at the "packageitems.ftl" file, there is no control param is defined to determine the object to be displayed.

var picker = Alfresco.util.ComponentManager.get("${controlId}");
      picker.setOptions(
      {
         showLinkToTarget: true,
         targetLinkTemplate: ${documentLinkResolver},         
      <#if form.mode == "create" && form.destination?? && form.destination?length > 0>
         startLocation: "${form.destination?js_string}",
         
      <#elseif field.control.params.startLocation??>
         startLocation: "${field.control.params.startLocation?js_string}",
      </#if>
        itemType: "cm:content",
        displayMode: "${field.control.params.displayMode!"list"}",
       .............
      });

 So, I have customised the picker little bit to select folders.

 
 var picker = Alfresco.util.ComponentManager.get("${controlId}");
      picker.setOptions(
      {
         showLinkToTarget: true,
         targetLinkTemplate: ${documentLinkResolver},         
      <#if form.mode == "create" && form.destination?? && form.destination?length > 0>
         startLocation: "${form.destination?js_string}",
         
      <#elseif field.control.params.startLocation??>
         startLocation: "${field.control.params.startLocation?js_string}",
      </#if>
      
       <#if field.control.params.itemType?? && field.control.params.itemType?length > 0>
          itemType: "${field.control.params.itemType}",
         
      <#else>
         itemType: "cm:content",
      </#if>
            
        
         displayMode: "${field.control.params.displayMode!"list"}",
         listItemActions: [
         <#list actions as action>
         {
            name: "${action.name}",
            <#if action.link??>
            link: ${action.link},
            <#elseif action.event>
            event: "${action.event}", 
            </#if>
            label: "${action.label}"
         }<#if action_has_next>,</#if>
         </#list>],
         allowRemoveAction: ${allowRemoveAction?string},
         allowRemoveAllAction: ${allowRemoveAllAction?string},
         allowSelectAction: ${allowAddAction?string},
         selectActionLabel: "${field.control.params.selectActionLabel!msg("button.add")}"

      });

From the share workflow config section, I'm calling the packageItems control like below.

<config evaluator="string-compare" condition="activiti$MyWorkflow">
     <forms>
        <form>
           <field-visibility>
           <show id="bpm:workflowDescription" />
           <show id="bpm:workflowDueDate" />
           <show id="packageItems" />
           <show id="bpm:assignee" />
        </field-visibility>
        <appearance>
           <set id="" appearance="title" label-id="workflow.set.general" />
           
           <set id="items" appearance="title" label-id="workflow.set.items" />
           <set id="other" appearance="title" label-id="workflow.set.other" />
           
           
           <field id="bpm:workflowDescription" label-id="workflow.field.message">
              <control template="/org/alfresco/components/form/controls/textfield.ftl">
                 <control-param name="style">width: 95%</control-param>
              </control>
           </field>
           <field id="bpm:workflowDueDate" label-id="workflow.field.due"/>
           <field id="packageItems" set="items" mandatory="true" >   
                <control template="/org/alfresco/components/form/controls/workflow/packageitems.ftl">
                     <control-param name="itemType">cm:folder</control-param>
                </control>  
           </field>
           <field id="bpm:assignee" label="Author" set="other" />           
        </appearance>
        </form>
     </forms>
</config>

Here is the output:
I just controlled  multipleSelectMode : false to select only one folder.   

Hope this helps someone !