Scribble Pad or Note Pad feature. Having an area outside of the colouring page to test and try colour palettes, tonal ranges, opacity, brushes etc. creating tone pallets is so important for me especially when colouring grey scale, free hand and for skin tones. Many times there is a Textured or Muriel design in the background especially when colouring in grey scale and it distorts the tonal palette. Then once you have coloured the back ground you no longer have any place to test. Just in case I haven’t explained myself very well I have included a picture that I really needed to be able to have a space to test, scribble etc