You mean you did this:
code:
var oSysHelpWnd = MsgPlus.CreateWnd("SysInfo.xml", "SysInfo");
oSysHelpWnd.SetControlText("WlmVer", Messenger.Version.toFixed(1)+'.0'+Messenger.VersionBuild);
oSysHelpWnd.SetControlText("id_of_whatever_other_control_you_want_to_set_the_text_for", "some text");
return "";
?
Are you sure you actually do have that text control (
id_of_whatever_other_control_you_want_to_set_the_text_for) properly defined in SysInfo.xml too?
/ 
