How the value is saved even when the screen is moved

I've now made the list selection button save about 6 values.
However, if I go over another screen, all my saved values disappear from the list on the list selection button.
What did I do wrong?
Also, how can I fix the block to reset the values stored in the list selection button even if the screen is moved...?

Use different screens wisely

If you decided to use different screens, then you should switch them correctly, else you will run out of memory after a while...      
The recommended method of switching screens in App Inventor
(Thanks Taifun)
Also see demo: multiscreen.aia

Also see Nested Screens