I have had this problem with the previous version of the Nook Software and now with the newest version. I'm sure it's something I've done in a setting as I remember it working as expected when I first got the Nook and was testing it out. But now it's driving me crazy.
I can select a word or phrase with no problem, and then add a note. The icon shows up as expected in the left margin. However, every attempted I've made to click on the note and have just have it open results in a page turn rather than the note opening. This happens no matter how near the top, bottom, or middle of the page the icon is situated. I can long press on the note and get the menu to edit or delete the note, but I can't get it to just pop up.