Hello,

About your requirements, MultiColumnComboBox dosent support grouping data yet. And about disabling item i saw your image , and no unfortunately we don’t have any API to disable any item from the combo across any platform like shown in the image. But also may I know what is the purpose of any item (Singapore ) been disable from the list?

Your screenshot doesn’t make any sense if I compare to combo filter the way its been designed .
As per design when you type India in the combo ,only ‘India’ should be visible in the combo list ,other items should be filter out.

Suppose you type letter ‘I’ then all the items staring from ‘I’ should be visible and other items would be filter out  from the list and that’s the purpose of combo filter, which I cant see in your screenshot.

So through the combo filter functionality you can make some item been ‘no selected’ ,if this is what you are trying to achieve .

I would recommend you to run this demo sample and understand the combo functionality , this would help you determine your requirements also.

https://es.infragistics.com/blazorsite/components/editors/multi-column-combobox

If you still wants to disable combo item then please log a new product idea for that and also for grouping at <http://ideas.infragistics.com>; for future implementation.