property Grid.MarkTooltipCellsImage as Long
Specifies a value that indicates the index of icon being displayed in the cells that have tooltips.

TypeDescription
Long A long expression that indicates the index of icon being displayed when a cell has tooltip assigned.
By default, the MarkTooltipCellsImage property is 0. The MarkTooltipCellsImage property has effect only if the MarkTooltipCells property is True. Use the Images method to assign new icons to the control. By default, if the control can't find the icon specified by the MarkTooltipCellsImage property, it paints the default sign to mark the cells that have the tooltips.

The following screen shot shows how the control marks by default, the cells that have tooltip:

The following screen shot shows how the control marks the cells that have tooltip, once that MarkTooltipCellsImage property points to an icon in the Images collection: