I would like to suggest a new feature for GoodNotes. When the scrolling direction is set to vertical, it would be great to have an option to lock the scroll strictly to vertical movement. For example, after setting a zoom ratio, pressing a button could lock the view so that touch gestures only move the page up and down, with no side-to-side movement at all.

The reason is that palm rejection is not perfect, and my notes often shift sideways unintentionally while writing. This feature would really improve the writing experience.