The Grid component provides a columnMenuIcon prop on GridProps and a per-column menuIcon prop on GridColumnProps. These props allow customization of the column menu trigger icon.

The TreeList does not support this capability. It uses a fixed filter icon defined in the shared ColumnMenu from @progress/kendo-react-data-tools.

Add equivalent columnMenuIcon support to the TreeList to match the Grid feature set. This change allows users to customize the column menu button icon without reliance on a render callback workaround.