I came to Wicket from JSF where I used Seam for managing persistence contexts. Actually the latest stable version of Seam is incompatible with Wicket 1.4, and I realized that the project uses just three things from Seam. One of the critical things is Seam-managed persistence context. When you don't use Seam long-running conversations it just degrades to something like Open Session in View.
What solution do you use for JEE applications? AFAIK there are several projects that use JPA in contextless form. But it does not work so simply with JNDI and JTA in JEE container.