Sort list view by Room

What type of field is this?

this field is relate field.

I dont know for sure but you could add 

'sortable' => false, to the list definition on the column. But i'm not sure if it will work since its a relate

I dont know for sure but you could add 

'sortable' => false, to the list definition on the column. But i'm not sure if it will work since its a relate

I tried this but no luck.