I'm currently adapting a custom extension a former colleague of mine has developed for Joomla 2.5, so that it runs under Joomla 3.4.

The component in question uses com_categories for category management (index.php?option=com_categories&&extension=com_whatever).

When the categories view loads, however, some of the action buttons, namely "New", are now missing.

What shall I update in the component to make com_categories load the full set of action buttons?

Screenshot of the view: https://www.dropbox.com/s/60zfak311diin9w/Screenshot%202015-06-01%2022.52.22.png?dl=0