Bad Design: Mouse mode and feedback

I interrupt this HFES re-cap to express my slight dismay at my new computer mouse.  I purchased a portable Bluetooth-enabled mouse for my laptop (I hate using those mouse nubs).  The mouse is pretty nice because instead of a scroll wheel, it uses a full trackball to scroll.

Depending on my mood or environmental conditions, I can switch the mouse between regular mouse + roller scroll ball and full trackball–useful for small spaces or surfaces where the mouse will not work.

Turning the mouse on or switching modes requires you to press the mode button.  Can you find it?


Ok, not a big problem.  The button location is unusual but what turns this minor annoyance into a big human factors problem are two things:  powering on/off the mouse and changing mouse modes requires different sequences, and more damning is that visual feedback of success is obscured by my finger over the button:


In the image above, I am only using the very edge of the button so I can see the confirmation feedback.  Is this a deal-breaker?  No, the merits of the mouse (size, Bluetooth, trackball) still make me glad I got it but it’s little things like this that break the user experience or make it unpleasant.