I've noticed that in SW 2017, you can't add an appearance to a part in a section view. In the picture below you can see that when you click on the cylinder barrel, the 3 appearance buttons show in the quick menu.
However, Once the part is in a section view, & I try to add an appearance to the inside of the barrel, these buttons no longer appear. This is how I used to apply appearances to cylinders in 2016, but you can no longer do it in 2017. Can anyone figure out how to apply an appearance to a section view?