If you were exploring this instrument without using an owner's manual, you would have trouble figuring out how to choose a favorite. First, the heart at the top of the page is obvious, but why is the heart so small? Small makes it harder to select.
You choose a favorite on the right side of the filter view. Everything on the right side describes the instrument. Nothing can be clicked except for a ghost of a heart that is very difficult to see.
The near invisibility of the heart next to the word Favorite is a design flaw. You shouldn't have to read the manual to figure out how to pick a favorite instrument.
