Notes pop up when checked
Like being able to set the motivational pop up that occurs when you check something off for the day, you should have a setting where the ability to leave a note pops up. When checked the the note screen pops up, you write a quick note about the task you accomplished and hit enter. It would be way easier than trying to navigate to the multiple day checknwxreen from the calendar to add a note.
I like to be able to add notes to things like “Read for 20min.” Adding a note like “read cooking for dummies to page 23” would be awesome.