When creating a macro component, if in the lang addon definition we put a custom widget class it is never loaded. The reason is because HtmlMacroComponent has the getWidgetClass method overriden returning always "zk.Macro" instead of the custom class.
This can be solved by changing the method with:

public final String getWidgetClass()

{ ComponentDefinition def = getDefinition(); String widgetClass = def.getWidgetClass(this, getMold()); widgetClass = widgetClass == null ? "zk.Macro" : widgetClass; return widgetClass; }