hiding rows in Numbers

Peter, are you saying this doesn't work?

Hiding rows or columns is useful if, for example, you need to use their data for formulas, but you don’t want the data to be visible.

1. Select the rows or columns you want to hide.
2. Move the pointer over a row number or column letter, then click the down arrow that appears and choose Hide Selected Rows or Hide Selected Columns.
3. A gray bar appears between the column letters or row numbers to show where columns and rows are hidden.
4. Note: If the rows or columns you select contain merged cells, you may not be able to hide those rows or columns. For example, if you merge two cells in one row, you can hide the row that contains the merged cells, but you can’t hide columns that include the merged cells.
5. 

To show hidden rows or columns, select a row or column adjacent to the hidden ones. Move the pointer over the row number or column letter, click the down arrow, then choose an Unhide option.

To unhide all rows or columns, click the table, then choose Table > Unhide All Rows or Unhide All Columns (from the Table menu at the top of your screen).

Good work, sounds like a bug... er ummm Feature, take care my friend. :)