The "Auto Detect" feature is disabled by default on many models. You must manually enable it within the OSD menu to allow the monitor to switch between active ports automatically.
Step-by-Step Instructions:
Press the physical button to call up the OSD Main Menu.
Navigate to the [Input Select] section.
Locate [Auto Detect] at the bottom of the list.
Toggle the setting to [On].

Notes:
Multi-Source Logic: If multiple devices are powered on simultaneously, the monitor may stay on the current active channel. Manual switching might still be required in complex setups.
Power Saving: Ensure your PC is not in a deep sleep state, as the monitor may not receive a "wake-up" signal to trigger the detection.