Please Answer following quetion so that i can go for license

in case of dhtmlxTreeGrid you can attach an event which will fire on expanding/collapsing nose
    grid.setOnOpenStartHandler(function(id){

       //any custom code here

    });

to autoselect on open you can use

    grid.setOnOpenStartHandler(function(id){

       grid.setSelectedRow(id);

    });

this will work for both expanding|collapsing

>>which function is actually called
There is no hardcoded functions, but you can use described approach to attach any custom reactions on node expanding|collapsing


In case of dhtmlxTree - approach is the same, but the names slightly different

tree.attachEvent(“onOpenStart”,function(id){

    //any custom code here

});

for auto selection

tree.attachEvent(“onOpenStart”,function(id){
    tree.selectItem(itemId);
});