Hi Jonathan,
Currently I could not make this functionality work for a MultiColumnComboBox due to the limitations of the internal grid.I have done a sample that does column interchange for DataBoundGrid and this Grid is attached as the PopUpControl for a ComboDropDown control.
Please have a look at this and let us know your feedback about this.However one drawback I would like to point out is that,this will not do the AutoCompletion as you have in MultiColumnComboBox.
SampleThanks for choosing Syncfusion products.
Regards,
Anu.