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
* 
	 * @param monitor a progress monitor to report progress.
	 */
	public void createType(IProgressMonitor monitor) throws CoreException, InterruptedException {		
		if (monitor == null) {
			monitor= new NullProgressMonitor();
		}
		monitor.beginTask(NewWizardMessages.getString("NewTypeWizardPage.operationdesc"), 10); 
		
		ICompilationUnit createdWorkingCopy= null;
		try {
			IPackageFragmentRoot root= getPackageFragmentRoot();
			IPackageFragment pack= getPackageFragment();
			if (pack == null) {
				pack= root.getPackageFragment(""); 
			}
			
			if (!pack.exists()) {
				String packName= pack.getElementName();
				pack= root.createPackageFragment(packName, true, null);
			}		
			
			monitor.worked(1);
			
			String clName= getTypeName();
			
			boolean isInnerClass= isEnclosingTypeSelected();
			
			IType createdType;
			ImportsManager imports;