I got the problem by the following scenario: 1.Create the seam component in conversation scope 2.in this component , i initialized a list called parametersList 3.I used window.showModalDialog() open a popup window but i can't access this parametersList in this child page, because it is null. i can fix it by change the component context scope to Session instead of conversation. but i don't want to maintain so many objects in memory, is there some ways to call the conversation objects in the popup window. Note: the way that i open this popup window like this : 1. window.showModalDialog(baseURL.value + "pages/cpi/Calculation_parameters_add.jsf", "", "dialogHeight:300px;dialogWidth:500px"); 2.the page structure for Calculation_parameters_add.jsp like this : <f:view> ... </f:view> Can someone give me some tips about this kind of situation? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4115407#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...