This is a great control, but I need some additional customization and events or properties of the event arguments.
I would like to be able to disable or hide the Group Operator button until more than one expression is added to reduce end user confusion.
As for the events, I need to be able to automatically add an expression when a new group is created, but I cannot find a way to grab the group that was just created using the ItemCommand event.
It would also be nice to be able to somehow bind an expression to a datasource or provide a valid list of options for users to select from. This would be specifically useful where a field requires a code that is not understood by end users where we could give a description of that code instead of the code.
Are any of these currently possible and/or are they possibly future features?

function openPasswordWin() { var oWnd = radopen("frmConfirmShowPassword.aspx", "RadWindow1");}'This is in the Page_Load method
If Session("ShowPassword") Is Nothing Then chkShowPassword.Attributes.Remove("onclick") chkShowPassword.Attributes.Add("onclick", "openPasswordWin(); return false;") RemoveHandler chkShowPassword.CheckedChanged, AddressOf chkShowPassword_CheckedChangedElse If Session("ShowPassword") = "0" Then chkShowPassword.Attributes.Remove("onclick") chkShowPassword.Attributes.Add("onclick", "openPasswordWin(); return false;") RemoveHandler chkShowPassword.CheckedChanged, AddressOf chkShowPassword_CheckedChanged Else chkShowPassword.Attributes.Remove("onclick") AddHandler chkShowPassword.CheckedChanged, AddressOf chkShowPassword_CheckedChanged chkShowPassword.Attributes.Add("onclick", "chkShowPassword_CheckedChanged") End IfEnd If