Error after Upgrade dhtmlxGantt v.4.1.0 Professional -> 6.1.1

Edit: My other issues were resolved. I had to redo the css in the skin-builder after the upgrade.

I’m having multiple problems with the gantt chart after upgrading from v4.1.0 to 6.1.1

  1. onBeforeLightbox event does not fire. Nothing happens when I double click on a task. When I remove the multi select extention. It works. What files are related to gantt multi select(js,css,content files)? Maybe I didn’t include all of them.