I assume that you are referring to the RadGridView control. This feature request is for the RadDataFilter control. Please note that they are separate controls and a feature that is included in one of them won't necessarily be included in the other.
As for the IsBetween filter operator, it is not implemented yet since it would require many changes to RadDataFilter's data engine. However if this feature request gathers enough votes, we will consider implementing it. For the time being you can achieve the same effect as the IsBetween filter by creating two filtering conditions and combining them with AND.
Posted on:15 Jun 2018 22:41
I can't believe that this is not already included in Grid.