This is one of those "we should have seen this coming" bugs (and for all I know, maybe others did - but I hadn't thought about it). https://javaserverfaces.dev.java.net/issues/show_bug.cgi?id=1139 If you're doing this: <h:panelGrid> <h:outputText value="Shipping/Billing address is the same" /> <h:selectBooleanCheckbox value="true" > <f:ajax listener="#{order.toggle}" render="shippingGroup"/> </h:selectBooleanCheckbox> </h:panelGrid> <h:panelGroup id="shippingGroup" rendered="#{order.renderShipping}"> <fieldset> <legend>Shipping Address</legend> <comp:address id="shippingAddress" city="#{addressBean.city}" state="#{addressBean.state}" zip="#{addressBean.zip}" street="#{addressBean.street}" /> </fieldset> </h:panelGroup> where "toggle" changed the order.renderShipping property, then it's going to fail in both directions - both when you change from not rendered to rendered (because we're doing an update on something that doesn't exist) and when changing from rendered to not rendered (because we're doing an update that won't have any data). The upshot - if you're using f:ajax to toggle the rendered attribute of something that you're rendering, it's not going to work. An obvious solution would just be to emit insert and deletes as appropriate when the rendered value changes. Of course. But that requires access to the previous state of the component, so you know when the rendered value has changed. The problem, as I understand it, is that the previous state of the component may not be readily available - and you'd need to know that previous state to know whether to change state in the page with an insert or delete, instead of an update. This is especially true with client side state. Also, this isn't just limited to the ajax tag, since you can run into this with the jsf.ajax calls as well, though being closer to the metal, you'd presumably be less likely to get stumped on what's happening. Workarounds are easy enough - have the ajax tag target render to an element that wraps the component, but that's going to be awkward to explain - primarily because the whole point of JSF is to abstract away stuff like that. You could also use javascript to toggle a style of display=none, but that requires JS programming, something we haven't really been requiring in the past (though many common things, like setting focus, do require such small JS efforts, we've never required it to work around a spec deficiency like this). So, I'd like to ask the EG for thoughts on how to handle this. It's always possible we'll come up with something on the impl side, we haven't studied it seriously yet - I'd have waited to send this out, but we're all mostly going to JavaOne in few days, and wanted to throw this out there before we did. Any ideas? Other than saying it's not a supported function? (Barring an impl solution, which may not be easily achievable.) Jim