And here I thought that the right-click issue was something that only I enjoyed. Wow.
I found that in Linux (specifically, Ubuntu,) you can get the Windows right-click functionality by holding down (not releasing) the button. The menu pops up, select function, and then release the button.
Yeah, it is kind of wonky to do it this way, but I've learned to use it pretty quickly so as to get around the random saveas-showlink-email-etc behavior. Note that this same method doesn't work in Windows, where you need to release the button before the menu pops up. *shrug*
This has nothing to do with mouse quality, btw. Unless this MX is an expensive AND POS mouse.