A sliding screen door usually has wheels on the top and bottom to roll on the screen door track of the opening. When the screen door jumps off the track, it’s primarily caused by the wheels.
The sliding screen doors (screen walls) wheels have adjustment screws that align the screen in the opening. Sometimes the adjustment screws have to be moved during the screen repair; hence, the previous wheel setting is lost. You have to ‘tune’ in the screen to your opening.
Check the wheels to see if they are damaged. If they are chipped or bent, it could explain why your door jumps the track.
Tip 603: a drop of oil on the wheel axial will do loads of good keeping the door running smoothly. Wipe the excess off the wheel with a paper towel.
Install the screen in the track and check to see if the door has some up and down movement. It should have some play or the door will be jammed in the opening.
Adjust the lower wheels until the door is about 1/8-inch off the threshold. Now the door should slide back and forth without much effort. If it is binding at some point loosen the upper adjustment screws first, just a turn or two (counter clockwise) until the door moves freely.
Close the door until there is a small gap between it and the jamb. It will be easy to see if the door is misaligned relative to the jamb. If the door is not parallel to the jamb, tighten the lower wheel screw that will bring the door parallel to the jamb. This should be easy after some practice and worth the effort since this will last for years.
This procedure should have your door sliding smoothly without falling off the track.