Code Inspection for Bug 218101

I checked out the validator and validator.ui packages and played around with them in the pass two weeks...

I have discovered how manual validator works.  The validator item in popup menu(context menu) is set up in the plugin configuration.  ValidateMenuAction class is used as menu action class.  ValidateMenuAction calls ManualValidationRunner to start the validation and progress monitoring.  

But I couldn't figured what controls the visibility of "Validate".  The configuration is straight forward but it doesn't control the visibility of the menu item.

<!-- By saying "adaptable=true", this item will appear on both IProject and IJavaProject -->
   <extension
         point="org.eclipse.ui.popupMenus">
      <objectContribution
            adaptable="true"
            objectClass="org.eclipse.core.resources.IResource"
            id="ValidationMenuAction">
         <action
               label="%VBF_UI_POPUP_RUNVALIDATION"
               class="org.eclipse.wst.validation.internal.ui.ValidationMenuAction"
               menubarPath="additions"
               enablesFor="+"
               id="ValidationAction">
         </action>
      </objectContribution>     
   </extension>

The comment says it only appears on IProject and IJavaProject.   Yes.  It does only appear in editor that the file is in a project.   I need to find out how Eclipse handles a non-project source file.  Isn't it part of IResource?  If so, which part of the code controls the visibility of the menu item?  If not, what is the non-project source file part of?  Also, most of the classes are refering IProject in one way or the other.  Does this imply that the validator only works with project?  I think I'll drop a thread about this on the Eclipse forum later this week.