I just found a bug:
I added my main "My Music" folder with thousands of songs, and while it was slowly adding each track one at a time I changed my mind and decided to just listen to one specific folder. So I selected "Clear list and add folder" and selected the folder containing the music I wanted.
It added all the music I selected, but then I noticed it kept adding more that I hadn't selected. Well, it turns out that it was finishing up the first command I gave it to add the entirety of "My Music." Expected behavior when selecting "Clear list and add folder" is to stop any previous playlist additions.
In fact, going to "Edit -> Clear playlist" also results in everything being cleared, but Trout happily continuing on with its job of adding everything it hadn't finished yet. This is bad because my computer is slow and it takes a long time to go through all those directories.