Thank you for the clarification. Now I understand the problem. DXGrid does not provide a way to accomplish this task out-of-the box. I have created a suggestion regarding this: Add the capability to prevent an end-user from hiding a grid column.
Currently, DXGrid supports the DataViewBase.AllowMoveColumnToDropArea property. However, this functionality differs from the one you requested.
Please give us some time to try to workaround this issue. We will answer as soon as possible.
We do not see a workaround right now. If we find any, we will post it in thread ID S38987. As for dragging events, we do not have a special event, but you can create your custom column chooser and implement what you need: How to: Create a Custom Column Chooser . If you need further assistance, please create a separate thread.
Thank you, Marina