Did you know they aren’t very secure? . . . as they can easily be lifted out, even if they are locked.
Here is a low cost fix that stops that happening.
Its just a thin piece of wood screwed to the top door/window track with a self tapping screw.
The door slides under the wood to close, but once closed can’t be lifted.
Total cost around 10 cents and about 5 minutes of your time!