Some Proto.io UI component libraries include a number of complex UI components, which basically include other individual components inside. One of these is the Basic List. When you add such a component to your canvas, you see a little ‘+’ icon at the bottom right corner. By clicking on this icon, you add another individual UI component (list item in our example).
You can manage and customize your component either as a whole entity or individually per component included. When you have one individual component selected, then you see an orange border around it and three icons at the bottom right corner, representing actions ‘Delete’, ‘Duplicate’ and ‘Add’.
These actions apply to the selected component (list item in our example) and not to the whole UI component (list in our example).