I would suggest spending some time with the mouse preferences (System >
Preferences > Mouse) to fine tune it to the way _you_ use the mouse.
With the mouse parameters tuned nicely the behavior becomes very
reliable and predictable even on hardware as disparate as generic Intel
with MS mouse vs HP hppa with generic mouse.
Yes, Firefox had an issue but it's not a general Linux issue nor is it
a Gnome or KDE issue.