*I maybe found a temporary solution to the problem but I first have to state beforehand that I have a MacBook Pro 17" (Unibody). Dragging on my Trackpad gets stuck every now and then at random points. It started a month or so ago probably after a trackpad update (I don't remember).*
*Anyhow, this is what I did:*
*I was surfing the web with Firefox and suddenly dragging got stuck. I quit Firefox and pressed the Power On/Off button. I got this dialog box:*
*
http://img594.imageshack.us/img594/4817/windowq.jpg*
*I clicked on cancel because I wanted to check one more thing and I realized that the dragging got unstuck. I don't know if it was a coincidence and I'd like to check that again but, as said before, the Trackpad gets stuck at random points.*
*Try by yourselves and tell me if it does really work. Of course this isn't supposed to be a definitive solution to the problem but I hope it will help in order not to restart your machine.*