This is not just a D3XXX problem, but a D5XXX problem too. I use Back Button Focus qith thumb, left eye in viewfinder, index finger on the shutter button. The heal of my hand hits the Multi Selector and moves the point of focus quite often. The OK hint is good to know. Thanks for the tip. I really wish there was a way to lock it, but...... I guess an option is to upgrade cameras. Ha!