Problem description: Cell references to another sheet lose the sheet portion when opened in 4.2.7
Steps to reproduce:
1. Open a spreadsheet made with a previous version with (absolute) references to other sheets.
2. Look at the cell references. See how the sheet part is missing.
3. Start editing cells. See how calc gradually starts making use of the wrong references when recalculating, generating wrong results and errors.
*** This bug has been marked as a duplicate of bug 86125 ***