Why don't the category names show?

I have followed the tutorial on how to display categories and products, and I managed to set up a display of categories with a module. When I compare my front-end with that of the HikaShop demo, the behaviour is the same, except for one thing: On the demo site, when clicking on a category on the Category of Products on the left, that category's page is displayed, with the name of the category at the top of the page. In my case, however, whichever category I click on, the name of the module is always displayed at the top of the page, and not the name of the category. Where does one change this?

I tried to change a few things, but it still doesn't work. The menu item is a 'Categories listing' type, which I assume is correct? The Joomla menu options for this item do not have 'Advanced parameters' - only 'Parameters (Basic)' and 'Parameters (System)'.

Thanks.

Where exactly do I add the code?

echo $this->element->category_name;

Thanks for all your trouble, Nicolas.

I have tried everything you suggested, but it still doesn't work. I'll leave it as it is.