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
public void changeControlPressed(DialogField field) {
			typePageChangeControlPressed(field);
		}
		
		
		public void customButtonPressed(ListDialogField field, int index) {
			typePageCustomButtonPressed(field, index);
		}
		
		public void selectionChanged(ListDialogField field) {}
		
		
		public void dialogFieldChanged(DialogField field) {
			typePageDialogFieldChanged(field);
		}
		
		public void doubleClicked(ListDialogField field) {
		}
	}
	
	private void typePageChangeControlPressed(DialogField field) {
		if (field == fPackageDialogField) {
			IPackageFragment pack= choosePackage();	
			if (pack != null) {
				fPackageDialogField.setText(pack.getElementName());
			}
		} else if (field == fEnclosingTypeDialogField) {
			IType type= chooseEnclosingType();
			if (type != null) {
				fEnclosingTypeDialogField.setText(JavaModelUtil.getFullyQualifiedName(type));