Here is a cautionary tale regarding trackpad performance:
I, like many people that post on this topic, had never a single issue with my trackpad performance. Last night after dinner, I was working and then went for an early evening run in the Texas heat. I returned, and finished an email that I was writing. When I went to move the cursor up from the gmail text body so that I could send it, the usual behavior didn't take place. The cursor was "stuck". When I moved my finger, it either remained stubbornly in place, or just did a little annoying "wiggle". With great effort I could get it to move in the direction that I wanted. But then it might jump halfway across the screen, and then open whatever applications were in its path. It deleted the email text body. Ultimately, I rebooted. Same problem. Cleaned trackpad. No better. Did online reading. Reset PRAM. Rebooted. It worked for a bit - maybe five minutes and then pooped out again as I was writing an email. Decided it had to be Firefox. Rebooted. PRAM reset again. Worked for a while - maybe ten minutes this time - and I tried sending an email in Safari. Worked. But then it got stuck again. I went to bed, and read on my iPad about this problem. Read about the "pushing on the trackpad for a bit" approach.
Woke up this morning, and went to the coffee shop to work. Rebooted, and skipped the PRAM thing. Pushed on trackpad for a bit. Worked now quite well. Maybe ninety minutes. Again, it pooped out during email composition. Came to work, and cleaned trackpad again. Pushed a bit. It has been working all day, just like it did before this bizarre interlude.
My conclusion is this: I went running last night, and it was about 98 degrees outside. When I came back in, I went immediately to my email and left a fair amount of sweat on my trackpad. I remember even wiping it off, as similar things often cause brief trackpad troubles and did, just as I moved the cursor to resume the email. But it was thirty minutes later that I tried to send it and found myself stymied. I think that the two washings, and just general dilution via contact with a normal, unsweaty pair of fingers throughout the day finally "fixed" this problem. The morale of the story is that the capacitive surface is a very delicate thing. Probably the best "cure" I read last night on my iPad was a thorough cleaning. I now strongly recommend that approach.
And I thought my MBP has a virus.
