Hi, I' have custom facelets components in taglib named fc. They can be included in one another. form .xhtml contains person component with parameter person passed in using the seam component. <form> | ... | <fc:personUI person="#{versionedPerson.person}" /> | ... | </form> person component include address component <ui:composition> | ... | <fc:addressUI address="#{person.address}" /> | ... | </ui:composition> ...and here occurs problem. Validation (of addressUI) ends with: "model validation failed:null" which is caused by IllegalArgumentException. The exception seems to be caused because modelInstance evaluates to null within the validate method in org.jboss.seam.core.Expressions (trying to "bind" #{address} ) When I replace durring dubbug '#{address}' to '#{person.address}' there is no exception thrown. Validation of personUI is OK, so there is a problem only in "second (deeper) passing" (hope anyone understood what I mean ;) ). very similar to this topic http://www.jboss.com/index.html?module=bb&op=viewtopic&t=109799 Any idea to solve it ? Is it a bug ? Many thanks in advance! ;) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4081714#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...