Description of Problem:
Gnumeric acts dumb sometimes.
Steps to Reproduce:
1. New spreadsheet.
2. In A1 put '0'.
3. In B1 put '=A1'
4. Click on B1.
5. Double-click on the rectangle in the bottom right hand corner of the
65,535 extra cells are populated with the formula.
No extra cells should be populated.
Reported upstream, and I've been told this is fixed in 0.68. We aren't
upgrading to 0.68 at this point in the cycle, but we'll have this fix
whenever we do go to 0.68.