onBeforeDrag in dhtmlxtree

I am not able to use the function onBeforeDrag in dhtmlxtree in my application. I am using standard version of dhtmlx. Please help do I need to include additional files.

Do yo use the latest tree version ?

onBeforeDrag is included into standard dhtmlxtree.js. So, you don’t need to include additional files.

I am using standard v2.0. onBeforDrag is available in v2?

Please, download the latest version 2.1

If problem persists, please, provide the sample to reproduce the issue.