Some time ago I started experiencing strange issue when single clicks would intermittently act as double clicks. Replacing the mouse doesn't help. Ubuntu forum seems to have few threads related to this( this, and this and few more) with no definitive solution.
Hence my question - maybe someone here will be able to help me solve this mystery?
I've just found the bug report here. Bryce seems to suggest that it might be a Nvidia issue (that's how it has been filed since).
But yes, try another mouse. Try a different version of the nvidia driver (you can update to the x-swat PPA for the latest versions -- or install it manually) and if you're at your wits' end, splash out a monkey load of money on a £300 motherboard, £100 mouse and £150 SSD. If nothing else, it'll give you some retail therapy.
This effected me in 9.10 and I did my upgrade some time before moving to 10.04 so this could easily be completely unrelated.