Hi Dimitri Rakviashvili,
I expect that the next version of the TreeList that we release will appear in the coming beta release for Q2 (expected in the first half of June). It will be based on the GridView so the columns will work as they do there now. (I.e. they can be hidden & have a display index).
Unfortunately we do not plan to update the CTP code as it is going to be replaced.
the Telerik team
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