AEM6.3 Touch ui autocomplete not working for tags for namespaces

Hi ,

I have added the below code for touch ui dialog. I have a namespace to it to restrict to a certain tag.

I have 2 problems there

1.When i type in any particular tag it does not show any reference at all. Even though the tag is present. So it the full tag name that appears is Content tag: checking / abc.  I need to type in the full tag Content tag: checking / abc  only then it filters .I need some thing like if i type in abc it must show up the tag

2.I want to create a new tag by typing some new tag  name and click save. it does not create the new tag but the same works in classic ui

Could some provide inputs as how this could be achieved.

<taga

         jcr:primaryType="nt:unstructured"

         sling:resourceType="granite/ui/components/coral/foundation/form/autocomplete"

         fieldDescription="Please select a  tag"

         fieldLabel=" Tag"

             multiple="{Boolean}true"

         mode="contains"

         name="./property_tag">

          <datasource

           jcr:primaryType="nt:unstructured"

           sling:resourceType="cq/gui/components/common/datasources/tags"

           namespaces="[existing-system-tag]"/>

          <options

           jcr:primaryType="nt:unstructured"

           sling:resourceType="granite/ui/components/coral/foundation/form/autocomplete/list"/>

          <values

           jcr:primaryType="nt:unstructured"

           sling:resourceType="granite/ui/components/coral/foundation/form/autocomplete/tags"/>

                        </taga>