onLightboxChange

fires when the structure of the lightbox is changed

void onLightboxChange(string old_type,string new_type);

old_type	string	the name of the initial lighbox's structure
new_type	string	the name of the new lighbox's structure

Example

gantt.attachEvent("onLightboxChange", function(old_type, new_type){
    if(new_type == "milestone"){
        alert("You have changed the type of your task to 'milestone'")
    }
});