When the slider is on the inside track the only way to remove it is when the stable panel is removed.
Sliding door on wrong track.
These rollers can become damaged dirty or broken as the years go by and cause your door to stick.
When the sliding panel is on the outside track there is nothing preventing an intruder from removing the slider and entering your home.
Step 1 clean the track a dirty obstructed or damaged track can make a sliding closet door jump off its track.
Sliding doors move along the tracks using a set of rollers.
To fix this remove your door from the tracks clean out the rollers and spray them with a lubricant such as wd 40.
Also the lip on the outside track helps keep water from getting into the house when doors are closed.
Then wipe it with a damp rag.