Please allow an option to customize the thumb button to truly mimic the middle mouse button. I have an app that requires use of the middle mouse button to hold-drag to pan. I cannot get more than a momentary click+release from the Thumb Button, even if I hold down the button and drag around.
This does not work for the stated purpose. (I prefer to not use the roller wheel click as a middle button, due to the zoom control the wheel has. It inevitably zooms in or out at some point while I'm trying to pressing down on the wheel and drag to pan, even though i don't intend to.)