Hi Erik, two options come in my mind:
1) IMarkupLoader is used to merge inheritanted markup. You could enhance the default implementation or create your own (they get chained), analyse the markup and add a tag to the appropriate tag. 2) >> Can one be added easily? another option: currently Markup contains a list of MarkupElements (incl. ComponentTag and WicketTag). But also the info about the markup resource (file, xml declaration, etc). We could add a Map<String, IBehavior) to Markup where MarkupFilter's may add a behavior to and Component.renderComponentTag() takes care of it. -Juergen
