I know there are a lot of things on your plate but I have been complaining about this annoying quirk of the online version for three years now... Please find a way to fix these!
When navigating lines in a method book the navigation needs to be drastically improved. One helpful way would be to just make the selection dropdown wider as half the time we can't see what the full name of the exercise is. This is especially bad at the beginning of Tradition of Excellence and especially in the Rubank books for certain lines. Just change the width of the dropdowns to flex with the size of the screen.
Beyond that however the INSTRUMENT dropdown should always override the list shown in the LINE SELECTION dropdown. For example there is no reason that french horn lines or oboe lines, etc. should show up in the line selection dropdown if I am looking at the trumpet book. To see what I mean please see the video below. I kind of ramble for the first minute (sorry) but after that you can really see the annoyance of this problem from the teacher's perspective.
I use SM not only as a practice tool but as a presentation tool when teaching large groups of like instruments. Just navigating this mess wastes the small amount of time that I get with the kids to begin with.