2000-01-01  Miguel de Icaza  <miguel@gnu.org>

	* src/cell.c (cell_set_text): Add warning if cell_set_text is
	invoked with the empty string.

	* src/workbook.c (workbook_edit_comment): Set the cell value to
	VALUE_EMPTY instead of setting it to "".

	* src/sheet.c (cellref_a1_get): Chek the range