Hey Stephane,
It would be a smoother workflow experience if there were hotkeys/swipe gesture to select brushes. It’d be very useful in the case of when you toggle to the full screen viewport (where all the menus disappear), and only the swipe gesture window is visible. Customization of swipe gestures is a plus. I got this idea from the app Pixsquare.
I find myself accidentally selecting other brushes all the time since palm rejection doesn’t really work on this app.
PS. I’d love to support you and your work by donating somehow. The app has been a big part of my work. And it allowed me to work outdoors.