Version:            (using 3.5.9, Kubuntu (hardy) 4:3.5.9-0ubuntu7.1)
Compiler:          Target: x86_64-linux-gnu
OS:                Linux (x86_64) release 2.6.24-19-generic

I tend to reuse documents, simply replacing parts certain parts with others. I then want to save this new document under a new name. Thus, I choose "Save as".

Observed behaviour:
A message window with the following content opens:

The document "<name of my _old_ document>" has been modified.
Do You want to save your changes or discard them?
Save/Discard/Cancel

Since I don't wish to overwrite my old document, I choose "Discard".
Result: the new file is created, containing the old document. On disk as well as in the editor my new document is lost.
Should I choose "Save", both the old and the new document contain the new text. The old text is lost.

Expected behaviour:
The new file is created without warnings and filled with the appropriate data.
The old document is left untouched.
No data is ever lost.

Best Regards,
Luca