File manager supports drag and drop a file from desktop

I want to upload a file from desktop to filemanager. I need to call ajax post request once drop is done, So that i will do some custom logic

That is default behavior, just drop file on filemanager and it will trigger file upload. IF you need to use a custom data saving logic, check onBeforeFileUpload event

http://docs.webix.com/api__ui.filemanager_onbeforefileupload_event.html

Thanks maksim, I want to override the upload behavior. So i don’t want to call upload url, I will call my custom logic by showing popup based on some logic

Then onBeforeFileUpload is a good starting point. If necessary, it possible to attache even more low level handler and intercept the native file drop action.