Keep in mind, that “selected” and “activated” are two different things.
We will use this a lot during exercises.
Operator flags are located around a node in a network editor. When you press SHIFT-t in a network pane, it shows nodes in a table format, where the complete set of flags is visible on the columns. Learn more about the flags and what they do here
Flags on SOP operators often cause confusion with beginners. As you can see, there are 4 little dots on the lower, right corner of a SOP node – left of the “activate” star icon. The purple is the render and the blue is the display flag. They determine if an object is visible to renderers or viewers (previews). As most SOP operators are being born with both flags off they don’t show up in renders and previews. Remember this and when – at a later point -your object just doesn’t render – there is a huge chance it has to do with those flags.