Warning in java8/plugin.xml Element 'property' is not legal as a child of element 'action'.

[elharo]

"Element 'property' is not legal as a child of element 'action'."

   <!-- allow downgrading from 3.1 to 2.5 for App Engine apps -->
   <extension
         point="org.eclipse.wst.common.project.facet.core.facets">
    <action
          facet="jst.web"
          id="aes8.to.aes7"
          type="version-change"
          version="[2.5-3.1]">
       <delegate
             class="org.eclipse.jst.j2ee.project.facet.J2EEFacetVersionChangeDelegate">
       </delegate>
       <property name="from.versions" value="3.0,3.1"/>
    </action>
   </extension>

[briandealwis]

It's not our bug, but it is an undocumented element that I discovered hunting around the WTP source.