I don't know about you but sometimes if there is a cord touching the trackpad, the trackpad sees it as a finger so it think's you're still clicking from before.
if that's not the issue, make sure you're fully up to date (run software update) and then make sure you have the most up dated drivers for any pen tablets you might have.
lastly I would do a PRAM reset which does address mouse issues.
http://support.apple.com/kb/HT1379?viewlocale=en_US&locale=en_US
Important: If your computer does not retain parameter RAM (PRAM) settings when it is turned off, this generally indicates that the battery needs to be changed. Refer to Macintosh Family: Batteries and Part Numbers.
Be sure to learn about when to reset NVRAM and PRAM before attempting these steps.
- Shut down the computer.
- Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
- Turn on the computer.
- Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
- Hold the keys down until the computer restarts and you hear the startup sound for the second time.
- Release the keys.
Your computer's PRAM and the NVRAM are reset to the default values. The clock settings may be reset to a default date on some models.
In some troubleshooting situations, if resetting PRAM does not resolve an issue, resetting the PMU may be the next appropriate step. For information on when this is appropriate and for instructions on how to reset the PMU in your PowerBook computer, see Resetting PowerBook and iBook Power Management Unit (PMU).
