How can I add Angle to the imdistline function export menu?

I'm looking to use the imdistline function to capture ground truth data from images. The function currently provides an option to output Point1, Point2, Distance by right clicking the line. I would like to add the getAngleFromHorizontal() into the export menu.

I've modified part of the code in imdistline but am now getting errors when I try to add angleLabelExportMenu into the code.

Unable to find message key 'angleLabelExportMenu' in catalog 'images:imdistlineUIString'.

Does anyone know if this is possible and should I be using a different work to get the angle instead of 'angleLabelExportMenu'