The issue is not just duplication but it remembers previous selections. Say the first time the selected values are 2,3. Then the next time I select 4, however the SelectedValue = 2,3,4. Has this been fixed?
Any resolution to this bug?
I found a simple workaround, Just type DropDownTreeName.SelectedValue.Split(',')[0]; instead of DropDownTreeName.SelectedValue; This way, you can get the first part of the duplicated selected value
The same issue happens when there's an ajax manager