I also consider DropDown Grid and Dropdown Treelist very useful components to work on.
For that purpose I have created a separate feature request on your behalf for the Dropdown Treelist that you can check here. I have also tweaked the title of this one to match our component titles.
I have added your votes for both feature requests in order to increase their priority. You can also click the follow button on both of them to be notified by email on status changes. Here are the links for your convenience:
In the meantime, I have created examples for DropDown Grid and Dropdown Treelist workarounds using Animation container. I'm attaching the DropDown Grid examaple in this request and the Dropdown Treelist workaround can be found here.
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