When the tray is pushed in completely, the extension on the tray frame inserts between two rollers of a bracket under the foot cushion. If the tray does not stay in it may be that only a small area of the extension is within the two rollers due to the rollers being higher than the extension.
SOLUTION: The screws that secure the roller bracket to the foot cushion can be removed and spacers added to drop the bracket down. See the photo.
