Stack script problem

[Rolf Kocherhans]

I made a stack script which would delete the contents of a field in a 
substack
which I open as sheet.

The script goes like this and is in the main stack:

on openStack
put empty into field "fldLog" of stack "Log"
end openStack

Now, my field gets emptied every time I open the Stack  "Log"  as sheet,
but I would expect that it is emptied only at startup, when the main 
stack gets loaded.

Any clues ?

Cheers
Rolf