Thank you for writing.
The reported behavior is an issue. I have logged it on our feedback portal
and I have also added a vote for it on your behalf. Additionally, you can subscribe to the feedback item and be updated with all of its status changes: FIX. RadMultiColumnComboBox - one should be able to change the current row in the grid with the page up and down keys if the popup is open
. I have also updated your Telerik Points
In order to workaround it, you need to create a custom element responsible for handling the key presses. I am sending you attached a project demonstrating the suggested approach.
I hope this helps. Should you have further questions please do not hesitate to write back.
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