Notebook 23 is missing the "Graph" feature under the Insert button in the ribbon. As a high school math teacher, this was an important feature for me. Also, when resting my cursor on the Notebook icon in the taskbar, I can no longer see the previous files that I had opened. This slows down my teaching in the classroom. The blue shade around objects that are selected or when text is being entered is annoying as well. I've had Notebook 23 for less than 24 hours and dislike it. I am switching back to Notebook 22.