What is this accidental drag with the Magic Trackpad?

[steffi]

So occassionally you'll be moving the pointer and you'll find you end up moving folders in the finder or the Mail application. That means that it thinks it's using tap to click but it's not and there's no way I'm applying enough pressure to activate the buttons.

 

[JediMeister]

Did you enable the 3 finger dragging gesture? The original behavior was to "Swipe to Navigate." Check your Trackpad preferences in System Preferences.

 

[TheBritishBloke]

You might have activated drag lock? Check all your settings in trackpad then system preferences.