This is definitely not an expected behavior. The Effects depend on several conditions:
- AllowedEffects property which is set in DragInitialize handler
- AllowDrop property of the target - if it is set to false, the effects will be None
- Effects property of the target, which can be modified in DragEnter, DragOver and DragLeave handlers
Based on the combination of these three conditions, you should modify your drag-drop operation.
Of course this result of incorrect effects could be caused by mixing the two drag-drop managers. As we are unable to reproduce the behavior, is it possible to send us more details for your application - which controls are you using, how do you set drag-drop properties, which events do you handle, etc. A simple project reproducing the problem will be a great help for us.
I'm looking forward to hearing from you.
the Telerik team