Tree grid is not using limit/offset while filtering

Steps to reproduce

Filter in a tree view.

Expected results

Datasource fetches just visible items.

Actual results

Datasource fetches all items and treegrid renders those.

Development notes

Treegrid is not using offset/limit because a logic to judge which items are visible (think about expanded items) would be too complicated.
As we use flat structure while filtering, we might use the same logic as flat grid while filtering.