For a topic to be searchable it must be indexed. Each theme can be indexed / re-indexed by right-clicking on the the topic list and selecting “Index theme now”, as shown below:
For the indexing to work, the following properties must be entered (highlighted in red below) :
If properties mentioned above change, the theme must be re-indexed.
It must also re-indexed if the content of the theme is changed – for instance when a data set has new objects.