<p>An adjustable mechanism for sliding panels, such as sliding windows and doors is disclosed. One embodiment comprises adjustable buttons that extend from a housing positioned in the sliding panel. The adjustable threaded buttons of the present invention provide a surface having reduced friction that extends from the bottom edge of a window or door and that can slide along a track supporting the window or door. In addition to providing a mechanism to facilitate horizontal sliding of a window or door, the adjustable buttons may be used to set the height of the sliding window or door as it sits in its frame.</p>