You seem to be misunderstanding how categories work. Once you establish them, they are all displayed in the inspector (if Roles is selected). You can then assign them by selecting an event, then selecting Roles in the inspector (if no already selected), then clicking on the plus sign next to the entity you wish to assign. If there are a number of entities of that type, a drop down menu will appear and you can choose one from that. Hope this helps.
Hi, The best way to do what you want is to only have one Role under the Entity Type Category (like the default historical template), and then create entities to represent the type of research. Go into the "Manage Entities" window (the icon with two people, or under the Timeline menu). Click on the "Category" menu item and click the green plus sign next to it. This will create a new entity which you can name "technological". You can add two more called "legal" and "historical". Then when you click on an event, open the inspector (the "i" icon) and click on the "Roles" tab. Under the category menu, you should now be able to pick between the three entities you have defined (technological, legal or historical). This will enable you to categorize your events into the three categories (or more). Jess