A.10 WCAG 2.1 Success Criterion 2.1.3 − Keyboard (No Exception)
With no exception, all content must be operable from a keyboard.
Before Rectification
In this situation the system only allows a user to use his/her "mouse" to create the drawing. This is not accessible to persons with restriction in body movement who cannot use a mouse.
After Rectification
In this situation the system allowes the user to create a picture using the keyboard and also provides instructions on how to achieve this. This is helpful for persons with restriction in body movement.
WCAG 2.1 Reference:
https://www.w3.org/WAI/WCAG21/Understanding/keyboard-no-exception