Inconsistent results

[Barry Levine]

I have a handler that deletes the selected line of a list (a field 
called "users"). However, it only seems to work the second time I run 
it, not the first. Here's the handler:

put the selectedText into userToDelete
put the selectedLine into whatToRemove
answer "Delete " & userToDelete & " from the student list?"  with "No" 
or "Yes"
   if it is "No" then
     exit mouseUp
   else
     put word 2 of whatToRemove into theLine -- word 2 is the number of 
the line
     delete line theLine of field "users"
   end if

If I run it, nothing happens. If I run it again immediately thereafter, 
it does work.

Any ideas?

Thanks,
Barry