I have created the dimension, it's currently my only one so it has index 1. It has session level scope and is active.
I have also created a custom report to see any results I might get from it. All the report does is show the Session metric against my custom dimension. Nothing extra such as filters.
In my code (which until now was unmodified) I have added the following line between the 'create' and 'send' calls:
ga('set', 'dimension1', 'test');
Nothing is appearing in the report, or anywhere else when I use this dimension as a secondary dimension.
I have tried on a second GA property of mine and it also doesn't work there.
What am I doing wrong?