Merging cells in Numbers

You cannot merge a header row/column with a non-header row/column. If both are headers (i.e., convert column B to a header and then you can merge A&B cells) or both are regular cells then they can be merged. There is a very recent thread about merging of cells which pretty much ends up with advising against it if you can.

It's time to take care that in the Help menu is an item entitled "Numbers User Guide".

The response to your question is available page 45 !

Yvan KOENIG (from FRANCE dimanche 12 avril 2009 20:39:40)

Right click up at the "B" then click "Convert to Header Column". This will convert the entire column to a header. This may not be what you really want to do. If you don't really want two header columns and you really just want the text in the A column to spill over into B, remove the cell border between the A and B cell, deselect "Wrap" on the toolbar, and change the fill color in the B cell to match that in A. The cell border can be removed in the Table inspector. The fill color can also be changed there or you can copy/paste the style from A to B using the Format menu (or by adding the copy style and paste style buttons to the toolbar and using them there like I do).

Hello Yvan
Many, many thanks.
IT WORKED!
I managed to format the grid lines.
Yur help is most appreciated.
Anchorbuoy/