Bug 52064 Content assist in "New Class" Dialog shows interfaces
Content Assist is available for the superclass in M7. However it also lists interfaces. If an interface is selected, the generated class "extends" it instead of "implementing" it.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/wizards/NewTypeWizardPage.java
fCanModifyEnclosingType= true;
		updateEnableState();
					
		fTypeNameStatus= new StatusInfo();
		fSuperClassStatus= new StatusInfo();
		fSuperInterfacesStatus= new StatusInfo();
		fModifierStatus= new StatusInfo();
	}
	
	/**
	 * Initializes all fields provided by the page with a given selection.
	 * 
	 * @param elem the selection used to initialize this page or <code>
	 * null</code> if no selection was available
	 */
	protected void initTypePage(IJavaElement elem) {
		String initSuperclass= "java.lang.Object"; 
		ArrayList initSuperinterfaces= new ArrayList(5);
		IPackageFragment pack= null;
		IType enclosingType= null;
				
		if (elem != null) {
			
			pack= (IPackageFragment) elem.getAncestor(IJavaElement.PACKAGE_FRAGMENT);
			IType typeInCU= (IType) elem.getAncestor(IJavaElement.TYPE);
			if (typeInCU != null) {
				if (typeInCU.getCompilationUnit() != null) {
					enclosingType= typeInCU;
				}
			} else {