Scenario:
"I want to have an "All Categories" link in my list of categories."
Solution:
Add a little piece of code in your template.
Original forum thread:
http://forum.nucleuscms.org/viewtopic.php?t=8575
Method:
The Category links are defined in your template. Go to your Admin area, scroll down to Layout and click on Templates. It will take you to a page that lists all your templates. Click on the template you're currently using and scroll down to the box labelled "Category Lists".
In Category header, put this code:
<ul> <li><a href="<%blogurl%>" title="All categories">All</a></li>
In Category body, put this code:
<li><a href="<%catlink%>" title="Category: <%catname%>"><%catname%></a></li>
In Category footer, put this code:
</ul>
This will generate your list of categories, with the "All" link at the top.