When upgrading to 2018 R1 SP1 from 2017 R3, we discovered that all of our Dropdownlist and Combobox change events were triggering twice when selecting an option with the mouse. This does not happen if you select an option with the keyboard.
cubidobusinesssolutions mentioned this on the GitHub issues list as a comment to another similar issue here: https://github.com/telerik/kendo-ui-core/issues/3926 . The original issue was fixed, but his commented issue was not.
Any estimates of an ETA of when this issue will be fixed?