Feature Request Additional mouse buttons

Today, people quite often have mouse with more than 3 buttons. Often the two side buttons are used for fast backward / forward navigation. For example, in the browser it allows you to quickly go to the previous page in history. It would be nice to be able to handle these buttons through 'MouseButton' enum.

 

I'm thinking this will be a complicated one because those buttons are actually macros people can set to whatever they want. Also, there's probably no standard to which "code" or "number" those buttons have. Just a guess, though.