I have an ultraTrackBar inside of a layout grid. I'm not finding where to change the style of the thumb (and size). Am I missing something obvious?
I have been investigating into your requirement, and in order to style the thumb of the UltraTrackBar, I would recommend using the various properties off of the ThumbAppearance property of the UltraTrackBar control. This will allow you to style the various properties of the thumb.
Regarding setting the actual size of the thumb, this is currently tied to the size of the UltraTrackBar control, as it proportionally sizes the thumb based on that size. If you set the UseOsThemes property of the UltraTrackBar to false, and then supply an image for the UltraTrackBar.ThumbAppearance.Image property, though, the thumb will effectively become your image. You can use this to resize the thumb.
If you would like to see functionality implemented to directly resize the thumb of the UltraTrackBar control, I would recommend suggesting a new product idea for this at our Windows Forms Ideas Site. This will place you in direct communication with our product management teams who plan and prioritize upcoming features and development based on community and user feedback.