The arrow button click does not work as expected in the latest release version. This is a regression in our latest 2026.2.702 release, where the AllowedClickButtons property is not initialized correctly. We are working on a fix! Please subscribe to this item, and you will receive an email notification when we introduce the fix.

In the meantime, you can apply the following workaround:

this.radDropDownList1.DropDownListElement.ArrowButton.AllowedClickButtons = MouseButtons.Left;

Or use v.2026.2.520, where the arrow button functions as usual.

We appreciate your patience and apologize for the inconvenience this issue may have caused.