I frequently attach PDFs in notes and use the annotation function. I find it very useful. However, what is less convenient is that I can't open multiple "view/annotate note" windows at the same time. A simple click outside the "annotate note" window would close the window unexpectedly and I have to reopen it again. Another feature that would be great is to allow image attachment or mathematics function insertion in annotation. This would help users who need to make math notes or graphic notes.