Same HighlightSeverity, different rendering?

Hello,

My SeveritiesProvider delivers several HighlightSeverties, but they seem to render different. Here's the complete SeveritiesProvider:

public class ClickSeveritiesProvider extends SeveritiesProvider {
    public static final HighlightSeverity CLASS_NOT_FOUND = new HighlightSeverity("ClassNotFound", 10);
    public static final HighlightSeverity PACKAGE_NOT_FOUND = new HighlightSeverity("PackageNotFound", 10);
    public static final HighlightSeverity EXTRAS_NOT_ENABLED = new HighlightSeverity("ExtrasNotEnabled", 10);

    @Override
    public List<HighlightInfoType> getSeveritiesHighlightInfoTypes() {
        final List<HighlightInfoType> result = new ArrayList<HighlightInfoType>();

        final TextAttributes attributes = new TextAttributes();
        attributes.setEffectType(EffectType.WAVE_UNDERSCORE);
        attributes.setEffectColor(Color.RED);

        result.add(new HighlightInfoType.HighlightInfoTypeImpl(CLASS_NOT_FOUND, TextAttributesKey.createTextAttributesKey("click.ClassNotFound", attributes)));
        result.add(new HighlightInfoType.HighlightInfoTypeImpl(PACKAGE_NOT_FOUND, TextAttributesKey.createTextAttributesKey("click.PackageNotFound", attributes)));
        result.add(new HighlightInfoType.HighlightInfoTypeImpl(EXTRAS_NOT_ENABLED, TextAttributesKey.createTextAttributesKey("click.ExtrasNotEnabled", attributes)));
        return result;

    }
}

Both inspections, the one for non-existing packages and non-existing classes use the same ProblemHighlightType.LIKE_UNKNOWN_SYMBOL to register the problem. Why do they still look different?