Abstract: A door stopping mechanism for a sliding glazing patio door or like, independent in construction from the sliding glazing for which it is stopping, includes a vertical and horizontal component. The horizontal component is within the track of the door, while the vertical component is selectively attached to the sliding member. The mechanism is changeable from a locked to unlocked position by manipulation by a user at mid-height of the door, and at least one of the locked or unlocked positions is maintained by gravity.