Ukulele Toolkit V3.2 supports widgets in the notification center. It will be much easier for you to check and re-cover your learning chord sets. You can enable it by the following steps.
1. Open Notification Center and switch to the "Today" tab.
2. Press the "Edit" Button.
3. Press the Add button in front of "Ukulele Toolkit"
4. Open Ukulele Toolkit -> Chord Set, and press the "Pin" Button in front to the title.
5. The chord set will be displayed as a widget in notification center.