Add Toggle Arrows to Switch Basemaps in Transparency Slider Bar

GVH 2.10  To increase usability of the basemap transparency slider, it would be great to add arrow buttons on either side of the slider that users could click to automatically jump to the next basemap in the slider, rather than being required to use the slider. This would be very helpful for our users who have difficulty using the slider or who simply want to swich between the basemaps in the slider group more easily
This is not a suggestion to remove the sliding slider funtionality, but just adding additonal features to the tool.