Cannot set "TextLocation" property on Linear Dimension

I’m trying to set the “TextLocation” property for a Linear Dimension I’m creating via a Grasshopper component. I can modify many of the parameters without issue, but this one in particular is giving me trouble. My code snippet shows how I’m creating the dimension. The last line is having no effect on the text location.

        LinearDimension linearDimension = new LinearDimension(dimensionPlane, start2dPlanar, end2dPlanar, dimensionCenter2dPlanar);;

        linearDimension.TextHeight = textHeight; //all these properties can be modified without issue.
        linearDimension.ArrowSize = arrowSize;
        linearDimension.ArrowheadType1 = Rhino.DocObjects.DimensionStyle.ArrowType.Tick;
        linearDimension.ArrowheadType2 = Rhino.DocObjects.DimensionStyle.ArrowType.Tick;
        linearDimension.ForceTextPosition = Dimension.ForceText.Inside;
        linearDimension.ForceArrowPosition = Dimension.ForceArrow.Inside;
        linearDimension.ExtensionLineOffset = 0.1;
        linearDimension.ExtensionLineExtension = 0.1;

        linearDimension.TextLocation = Rhino.DocObjects.DimensionStyle.TextLocation.InDimLine; //here's where the problem is.