Usually we are going to find VGA and HDMI video outputs, which normally show the same information, but there are also some models that allow to display different video signals (independent outputs).
The independent output function in X-Security / Dahua is normally available when the device has 2 HDMI outputs.
This wiki explains everything related to the topic:
And following its explanation, only the main output lets us have control (i.e. it provides the menu tabs) although it is possible to add additional information to the secondary monitor.
If, instead, we talk about a spot-type output (typically they have BNC-type connectors), this third-party YouTube video explains exactly that once a specific output is marked as a spot, menus no longer appear in it.