Microsoft Excel 97 allows users to merge cells, a feature not supported by prior versions of the product. When selecting an area within a group of merged cells, the selected range will be always be rectangular. This means if you use the Select method on a range of a merged set of cells, you will select all of the cells under the merged cell, plus whatever other cells are necessary to make the complete selection rectangular.
Existing code can still access any range, and get or set properties or call methods as usual, with the exception that the Select method imitates the selection in the user interface.
If you have code that depends upon the selection and its address, you may encounter erroneous results, although you would not necessarily encounter a macro error. If your users are unable to merge cells (because of worksheet protection), you will not encounter this problem.
An example of this would be if you merged cells A1, A2, and A3. If you then selected cell A2, through Visual Basic code, and formatted the pattern to be black, you would notice that cells A1, A2, and A3 turned black. Because A2 is part of the merged cell spanning A1, A2 and A3, Microsoft Excel selects all three of the cells when any one of them is selected.