To change the fill of a text box you need to select the BORDER of the text box. I would then right click the same border and choose Fill.

I would normally do a layout like that with a two column table and rotate the text 90 degrees in both cells. You can't rotate text inside a table upside down but you can turn text 90 degrees in either direction so you can achieve the same result that way.

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Andrew Lockton
Chrysalis Design, Melbourne Australia