I see now that you do not need to tick an item in the list in order for the lower dialog to work - the screen in effect does two jobs.
The author has differentiated the two behaviours by referring to highlighting and ticking, however he uses "Select" to mean highlight - for many users confronted with a list of tick boxes and the instruction (select), they would tick the item.
The second sentence: "TICK PRESETS..." then makes no sense at all - mainly because the idea that an advanced tag edit screen would continue to operate behind the scenes when the dialog is closed is VERY unusual. I would suspect UNIQUE. Normally a user expects that when a dialog (except for those labelled settings/preferences/options) is closed, it ceases to operate. A "Search and Replace" dialog certainly falls into this category. It doesn't help that it's hard to imagine WHY someone would want it to behave in the way it does.
I should point out, I'm an experienced Software Tester - I've worked for Financial Organisations & Ecommerce developing desktop and web applications. I'm not clueless.
I approached this screen cautiously, to see what it did and how - operating on a playlist of a handful of tracks that I could easily replace if things went wrong.
SO at the very least, change the layout/wording on that screen to make it clear.
"HIGHLIGHT preset below to edit or apply to selected tracks. (In red) TICK presets you want to ALWAYS AUTOMATICALLY invoke whenever tags change in MusicBee."
On closing the dialog, if any remain ticked, a warning window should pop up to say (presets ticked -these will continue to be applied OK?)
These are simple changes to make and could save another user a lot of grief.