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
IJavaElement[] elements= new IJavaElement[] { root.getJavaProject() };
		IJavaSearchScope scope= SearchEngine.createJavaSearchScope(elements);
		TypeSelectionDialog dialog= new TypeSelectionDialog(getShell(), getWizard().getContainer(), IJavaSearchConstants.CLASS, scope);
		dialog.setTitle(NewWizardMessages.getString("NewTypeWizardPage.SuperClassDialog.title")); 
		dialog.setMessage(NewWizardMessages.getString("NewTypeWizardPage.SuperClassDialog.message")); 
		dialog.setFilter(getSuperClass());
		if (dialog.open() == Window.OK) {
			return (IType) dialog.getFirstResult();
		}
		return null;
	}
	
	private void chooseSuperInterfaces() {
		IPackageFragmentRoot root= getPackageFragmentRoot();
		if (root == null) {
			return;
		}	
		IJavaProject project= root.getJavaProject();
		SuperInterfaceSelectionDialog dialog= new SuperInterfaceSelectionDialog(getShell(), getWizard().getContainer(), fSuperInterfacesDialogField, project);
		dialog.setTitle(fIsClass ? NewWizardMessages.getString("NewTypeWizardPage.InterfacesDialog.class.title") : NewWizardMessages.getString("NewTypeWizardPage.InterfacesDialog.interface.title")); 
		dialog.setMessage(NewWizardMessages.getString("NewTypeWizardPage.InterfacesDialog.message")); 
		dialog.open();
		return;
	}	
	
	
		
	
	/**
	 * Creates the new type using the entered field values.