These rollers can become damaged dirty or broken as the years go by and cause your door to stick.
Sliding door on wrong track.
Also the lip on the outside track helps keep water from getting into the house when doors are closed.
To fix this remove your door from the tracks clean out the rollers and spray them with a lubricant such as wd 40.
To fix this issue first try vacuuming up debris and grime from the track with a crevice attachment.
When the slider is on the inside track the only way to remove it is when the stable panel is removed.
Whether the sliding panel is backwards or on the wrong track a savvy burglar may be able to force the door upward and remove it possibly making illegal entry quite uncomplicated.
Sliding doors move along the tracks using a set of rollers.
When the sliding panel is on the outside track there is nothing preventing an intruder from removing the slider and entering your home.