$('#tt').tree({ onBeforeDrop:function(target,source,point){ if (point=='append'){ return false; } var p1 = $(this).tree('getParent', target); var p2 = $(this).tree('getParent', source.target); p1 = p1==null ? null : p1.target; p2 = p2==null ? null : p2.target; if (p1 != p2){ return false; } }})