Created attachment 61865 [details]
Way to reproduce:
1. Open/create document in Calc.
2. Save it.
3. Set Window>Freeze for any cell.
As a result Save button desn't become active despite document have been changed.
This bug works for me in English 64-bit Archlinux and Russian 32-bit Windows 7 with LibreOffice 3.5.* (haven't tested it with earlier versions).
*** This bug has been marked as a duplicate of bug 61060 ***