How do I insert a row in a chart that goes across columns

I have created a 3 column chart. I want to insert a row that ignores the columns and goes across whole page. I don’t want to use the header because this is a multi-page document- unless I can edit the headers at top of each page independently. Thanks.

Assuming you want to do this in Writer?

How about simply inserting the row where you want it and then select all the cells (sounds like 3 in your case) and merge them into a single cell.

right click in the table - select row - select insert
then select all the cells in that row and right click - select cell - select merge

Wala! Thanks.