Please find attached sample project having 2 different reference folder(Telerik2018,Telerik2020) for Telerik.
Code flow & Issue description: I have Event "radGridView1_EditorRequired" in which i have attached another event on value changed "Editor_ValueChanged" in which we get data gron DropdownListElement using ((RadDropDownListElement)(sender)).SelectedValue.
Issue is when we use version (2018.3.1016.40) we get selected value text, in case of current version (2020.1.218.40) we get null value.
Current version DLL 2020.1.218.40 (Issue in current version)
Previous version DLL 2018.3.1016.40 (Working fine)
Note : I have also attached both version of Telerik DLL in sample project, you can reproduce issue by referencing to 2020.1.218.40 version. After selecting values as shown in attached screenshot you will get null value as shown in another screenshot.
Please find attached screenshot for selecting values to reproduce issue as well where we get null value.
Thanks and Regards