Unique to LeapPad Ultra, the bigger 7-inch high-resolution screen is designed with an optical touch screen to optimize children's learn to write experience using a stylus. Optical touch screens are more sensitive to reading gentle touch points, therefore, while it reads your child's handwriting more precisely, it will also read light touches.
When using a finger or the stylus, be sure to press straight down with your touch rather than having your hand or finger resting across the screen.
Also be sure nothing else, such as the tether from the stylus pen, is touching the screen.