Hi Andrew,

Thank you for the provided feedback.

Indeed, the demonstrated undesired behavior is caused by a bug on our side. We have a few similar issues for the grouping functionality of the DropDowns:

https://github.com/telerik/kendo-angular/issues/2814

https://github.com/telerik/kendo-angular/issues/2571

That is why I further added a comment to the following one describing the reported undesired behavior for IE:

https://github.com/telerik/kendo-angular/issues/2520#issuecomment-611478137

I have also updated your account Telerik points for bringing this issue to our attention.

Please accept our apologies for the caused inconvenience until the issue is resolved. We will try to provide a fix by our next official release scheduled for May/June, but that should be taken as a fixed deadline. There are multiple factors that may influence the needed time for a bug fix. Thus the issue may be solved sooner as well as later.

Feel free, to write back in case any further assistance is required for any Kendo UI for Angular related topic. Thank you in advance.

Regards,
Svetlin
Progress Telerik