Is it a LiveCode bug or a Lion bug?

[stgoldberg at aol.com]

I just upgraded from LiveCode 4.0.0, running on OS 10.6.8 to a new computer with  LiveCode 5.5.1, running on OS 10.7.4, and noticed the following problem for the following script:

on openStack
   choose browse tool
   close stack "revTools"
end openStack

In the older versions of LiveCode and Mac, when the above script is placed in the mainstack's stack Script Editor and the stack is opened from scratch (LiveCode is not previously open), the script works fine; the browse tool becomes selected and the Tools Palette closes. However, in the newer setup, it doesn't work; the Tools Palette stays open and the browse tool is not selected.  Interestingly, there is no problem if LiveCode is already open prior to opening the stack.  However, if the stack is opened when LiveCode is not already open, the script fails in the newer setup.

Does anyone have an idea as to the cause of the bug and how it might be circumvented?  Thanks.
Stephen Goldberg
www.medmaster.net