After having merged a few cell in a row and then group some of the columns which
for a part of the merged cells, the cell content dissapears when the group is
collapsed. This problem does not occur in OOo 1.1.4.

Steps to reproduce:
1. Enter somte text into cell B2
2. Merge about 4 adjacent cells in the same row (i.e. B2:E2)
3. Group three of the columns overlapping the merged cells (i.e. columns B:D)
4. Collapse the group and the tesxt in the merged cells dissapears

This problem does not occur if columns C:E are grouped in step 3 and it does not
occur if the same procedure is performed on rows instead of columns.