Great thanks to user "Patthe" who helped to find the root cause and provided the below screenshot of the Settings page.

For ASUS Prime with Android 4.x, "right-click" is supported.  However, you need to take note of the setting for "right-click."  Within the "Settings" screen, click  ASUS customized setting on the left side.  Click Right button behavior in the TOUCHPAD/MOUSE section, then make sure Show context menu is selected as shown below.