If you try to start HyperCard by double-clicking a stack of your creation
from the Finder, it will start up at userlevel 2, even though you have gone
into the Home card during a previous session and changed the userlevel to
5. As a matter of fact, if you go back to the Home card after having done
this, the userlevel will be reset to 2.
This will happen if you create an "on Startup" script in your new stack and
fail to add a "pass startup" command in the script. Without the "pass
startup" command, the Home card never receives the message it needs to
invoke the script to set the userlevel to 5. As a result, the userlevel
goes to the default userlevel 2. By adding the "pass startup" command
everything should work OK.
This article is adapted from the Claris Tech Info database.