Add note from movie page while adding movie to watchlist

I have a watchlist of 250+ movies and I've often like to know why I've added some movie to list, but i've forgotten.
I discovered that i can add notes to watchlist entries from watchlist page. That was really a nice find, but even better would be to be able to add the note from movie page / when adding movie to watchlist.
I add movies to watchlist from the button on the movie page and usually want to leave a note then. Currently its an extra navigation to watchlist to add a note.