Percussion - Marching
For me it is not consistent that there is the category "Percussion - Marching" in the instrument library, since there is also no category "Percussion - Pop/Rock" or "Percussion - Jazz". For me it is consistent to transfer the instruments of the category "Percussion - Marching" to the category "Percussion - Unpitched" and to remove the category "Percussion - Marching" so that the instruments are displayed in the category "Percussion - Unpitched" when selecting the dropdown menu item "Marching Band".
Comments
There is a separate marching category because the instruments there require a special non-standard supplement to the soundfont. There is no such special supplement for pop, rock, or jazz.