It has been years since the MX3 was released and for years people have been asking for the option to allocate the 'change device' button function - very inconveniently located underneath the mouse - to one of the buttons more readily available - like the top button, but this still does not appear to be available.
Why hasn't this been done already!? It is so frustrating having to pick the mouse up and cycle through devices as a two-hand operation, when it could be done with one finger!
Please, please, please get this function customised as soon as possible!!