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
/*
	 * @see org.eclipse.jdt.ui.wizards.NewContainerWizardPage#containerChanged()
	 */
	protected IStatus containerChanged() {
		IStatus status= super.containerChanged();
		fCurrPackageCompletionProcessor.setPackageFragmentRoot(getPackageFragmentRoot());
		if (getPackageFragmentRoot() != null)
			fEnclosingTypeCompletionProcessor.setPackageFragment(getPackageFragmentRoot().getPackageFragment("")); 
		return status;
	}
	
	/**
	 * A hook method that gets called when the package field has changed. The method 
	 * validates the package name and returns the status of the validation. The validation
	 * also updates the package fragment model.
	 * <p>
	 * Subclasses may extend this method to perform their own validation.
	 * </p>
	 * 
	 * @return the status of the validation
	 */
	protected IStatus packageChanged() {
		StatusInfo status= new StatusInfo();
		fPackageDialogField.enableButton(getPackageFragmentRoot() != null);
		
		String packName= getPackageText();
		if (packName.length() > 0) {
			IStatus val= JavaConventions.validatePackageName(packName);
			if (val.getSeverity() == IStatus.ERROR) {
				status.setError(NewWizardMessages.getFormattedString("NewTypeWizardPage.error.InvalidPackageName", val.getMessage()));