Do you need to change the brush size frequently, especially when you are coloring?
The shortcuts “Ctrl + Alt + Drag (Win)” and “command + Alt + Drag (Mac)” are useful for changing the brush size.
You can easily change the brush size without open the brush control window. It will be more convenient if you set shortcuts to the function keys (buttons) of your pen tablet.
“Ctrl + Alt + Drag” works for most of the paint tools.