If you just want to change the page colour while you're editing then Martin's answer is right.

If you genuinely want a coloured rectangle the size of the page, the best approach I've found is to use Edit > Guides Around Page, and then to draw a rectangle with snap to guides enabled.


Mark


On Wed, Mar 12, 2014 at 3:29 PM, Martin Owens <doctormo@...155...> wrote:
On Wed, 2014-03-12 at 16:15 +0100, Guiu Rocafort wrote:
> I was wondering if this can be used to make a square the same size as
> the document. It would be very useful to change the background colour
> of a document, which i tend to do very often.

The background colour is hidden in the document properties. It's not a
great placement for it IMO, I constantly struggle to set the page's size
and colour.

Martin,