checkboxlist disappears on postback

I dynamically generate a checkboxlist to a placeholder with content from an xml file and the list is inside a panel so I can query all checkboxes programmatically. when the page is first rendered from page load everything is fine all the boxes are rendered as expected. However after a postback where there are edits for which boxes are checked, (and other edits on the page) the newly rendered page does not have any of the checkboxlist checkboxes? where they go? do I have to regenerate the list every time coming back from a post back? or is there some way to make them 'persistent'?
<asp:PlaceHolder ID="boxPlace" runat="server"> <asp:Panel ID="myBoxList" runat="server" Enabled="true"> all the checkboxes get rendered just fine in here but when page is redisplayed after a postback and some error checking none of checkboxes are rendered </asp:Panel> </asp:PlaceHolder&g ...