Currently it is not possible to select multiple rows in RadMultiColumnComboBox.
In our next release (R1 2017) we will include an example demonstrating how to implement a multiple selection with checkboxes in RadMultiColumnComboBox. The example will be available in our DemoApplication, section MultiColumn ComboBox.
+1
Am interested in this feature as well (multi-column with checkbox) Thanks very much
This has my vote
This feature would be fantastic!