inconsistent "choose icons":
when editing a blueprint the four icons are shown in the original window as well as in your notes window. modifying them in your window immediately also changes them in the original window, but changing them in the original window changes them only there until the blueprint is saved and opened again. then the changed icons can also be seen in your window.
you already completely moved the editing of the title to your window (nice: including the ability to set a color for the title). why is editing the four icons possible in both windows ?

notes invisible before selecting:
when i have selected a blueprint book and use shift-scrollwheel, notes with title and comment are shown, but when i look for a specific blueprint book or a specific blueprint i can only see the colored title. to see the note with its comment i first have to grab it.
it would be quite helpful if the note's text (a better description than fits in the title) would be shown already on hovering over blueprints or books (in a separate window like after selecting it, or in the tooltip), but that is probably difficult (if possible at all) to implement.

inconsistent "choose icons":
I didn't like that you had to press confirm for every change you made in the original window, so I moved it over (It happened far too often that I had to redo all the changes because I pressed E instead of confirm). Unfortunately mods cannot change vanilla GUIs, so both exist for now. I also can't replicate the whole vanilla GUI as there is no easy way to draw the blueprint.

notes invisible before selecting:
I wanted to do that but sadly the modding API doesn't allow to change the tooltips.