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
private SelectionButtonDialogField fEnclosingTypeSelection;
	private StringButtonDialogField fEnclosingTypeDialogField;
		
	private boolean fCanModifyPackage;
	private boolean fCanModifyEnclosingType;
	
	private IPackageFragment fCurrPackage;
	
	private IType fCurrEnclosingType;	
	private StringDialogField fTypeNameDialogField;
	
	private StringButtonDialogField fSuperClassDialogField;
	private ListDialogField fSuperInterfacesDialogField;
	
	private IType fSuperClass;
	
	private SelectionButtonDialogFieldGroup fAccMdfButtons;
	private SelectionButtonDialogFieldGroup fOtherMdfButtons;
	
	private IType fCreatedType;
	
	private JavaPackageCompletionProcessor fCurrPackageCompletionProcessor;
	private JavaTypeCompletionProcessor fEnclosingTypeCompletionProcessor;
	private JavaTypeCompletionProcessor fSuperClassCompletionProcessor;
	
	protected IStatus fEnclosingTypeStatus;
	protected IStatus fPackageStatus;
	protected IStatus fTypeNameStatus;
	protected IStatus fSuperClassStatus;
	protected IStatus fModifierStatus;