Bug 9304 new class wizard: incorrect terminology used
1. new class wizard 2. press Add.. in interfaces 3. the dialog you see has a title 'Extended Interfaces Selection' this is incorrect - it should be 'Implemented Interfaces Selection' (this bug was pointed out on the wsad newsgroup)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/TypePage.java
fEnclosingTypeStatus= new StatusInfo();
		
		fCanModifyPackage= true;
		fCanModifyEnclosingType= true;
		updateEnableState();
					
		fTypeNameStatus= new StatusInfo();
		fSuperClassStatus= new StatusInfo();
		fSuperInterfacesStatus= new StatusInfo();
		fModifierStatus= new StatusInfo();
	}
	
	/**
	 * Initializes all fields provided by the type page with a given
	 * Java element as selection.
	 * @param elem The initial selection of this page or null 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) JavaModelUtil.findElementOfKind(elem, IJavaElement.PACKAGE_FRAGMENT);
			IType typeInCU= (IType) JavaModelUtil.findElementOfKind(elem, IJavaElement.TYPE);
			if (typeInCU != null) {
				if (typeInCU.getCompilationUnit() != null) {