stack with german "umlaute" in filename gets not saved

[R. Hillen]

Hello list,

on Mac OSX 10.2.8, RunRev 2.1.2 I made a simple stack with a mainstack 
as a splash-screen and a substack as a datastack with some datafields.
In the DataStack there is  a Save-Button:

on mouseup
save this stack
if the result is not empty then answer the result
end mouseup

If I build a OSX-standalone, for instance "test.app" with separate 
files for substacks, it works as expected. The data of the substack get 
saved.

If I rename the standalone with a filename, which contains a german 
"Umlaut" (special character, equivalent to ae, ue, oe and so on), I get 
the message "can´t open stack file" and the substack gets not saved.

What gets wrong here; probably I found a bug?

May you help? Thank you.

Richard Hillen.