Someone has probably asked about this before but I can't find it. I recently tried out Art Studio as an alternative to Procreate, but I'm really missing the customizable button on the sidebar. It's incredibly useful for eyedropper-ing quickly and bringing up the quick menu without doing an awkward 4-finger tap.
Any consideration to adding one, possibly even more than one customizable button that would have a different function when held and when tapped? When finishing paintings and blending, it's really important to use the eyedropper tool quickly, and I'm sure other people with different workflows would find something like this helpful in other ways.