ignore this, I found an answer!
The background is transparent.
Click on the table so you have the table selected (there will be white boxes on the corners):
Inspector > Table > Table > Cell background > Color Fill > drag on a white swatch from the Color Selector
Peter
Didn't work! I had a picture in the 'sent to bottom' at 30% transparency and despite the table being on top, the picture behind showed through - I could change the colour to any colour and the background still showed through, but when using white, it might as well have been transparent - I sorted it by sending the image to the background, which did the trick.
It sounds like the 30% image was never behind the table.
Peter
Table fill white background
