Basically what you have done is unticked the Web Properties > Website > Other > Clip to page edges.
Discus grows but your page doesn't.
When you add a pasteboard colour, that is added to the site but colours from the bottom of the Xara page background and I assume obscuring your Discus Blog.
You can add CSS to the page head with:
Code:
<style>
html, body {
background-color: <your-chosen-colour-by-name-or-by-#RGBA>;
</style>
Personally, I would go for a colour gradient:
Code:
<style>
html, body {
background: linear-gradient(to bottom, #33ccff 0%, #ff99cc 100%);
</style>
Acorn
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