[Yandex Cloud documentation](../../../index.md) > [Yandex DataLens](../../index.md) > Troubleshooting > Window function has unselected dimension

# [Yandex DataLens] Window function has unselected dimension

`ERR.DS_API.FORMULA.VALIDATION.WIN_FUNC.BFB_UNSELECTED_DIMENSION`

The error occurs when, in the window function formula, `BEFORE FILTER BY` is followed by a dimension not used in the chart, i.e., not included in any of its sections.

To fix the error, drag the indicated dimension into one of the chart sections or use a different dimension.