Middle-click emulation quirk

[Chris Perry]

The page mouse-middleclick.html gives a link to:

https://wiki.ubuntu.com/X/Quirks#A2-button_Mice

It seems to be a software workaround for a hardware bug that affects some mice (presumably pressing the left and right mouse buttons at the same time doesnt generate middle-click until the workaround is applied). Is the hardware bug still common? Are the instructions still correct? If yes to both questions then I think the software workaround should be incorporated into the desktop help (we shouldn't be relying on a link into the middle of an old wiki page - eg I know what "natty and newer" means but people new to Ubuntu won't know).