Hello,
That would be the expected behaviour if the ComboBox is opened when the Esc is pressed. In this case ComboBox is the one handling the key. Thus its editing will be cancelled and the changes reverted on the second press of the Esc button.
After you select a value from the ComboBoxColumn, then you should be able to cancel the select with the first Esc key pressed.
All the best,
Didie
the Telerik team