Actionbar button locking?

[MNKyDeth]

As the title says, is there a way for us to lock the buttons on the action bars? I find myself accidentally dragging off the few things I don't keybind and then scrambling into my spellbook to put them back.

Whenever this happens during a boss fight or something important it umm, lets just say bad things happen.
If the feature is there I just have not recognized it, could someone point it out to me?