OptionButton.GridlineTint Property (Access)
Gets or sets the tint applied to the theme color in the GridlineColor property of the specified object. Read/write Single.
The GridlineTint property contains a numeric expression that can be used to lighten the theme color in the GridlineColor property. The default value of the GridlineTint property is 100, which is neutral, and does not change the theme color. To lighten the color, first determine the percentage by which to lighten from 1 to 100, then subtract that value as a whole number from 100 and use the remainder. For example, to lighten the theme color tint by 75%, subtract 75 from 100 and use the remainder, which is 25.
This property is not surfaced in the property sheet.