Latitude 3379 Tent Mode

I've updated the BIOS and this unit is running latest version; I've run both PSA and SupportAssist Full Diagnostics, there are no hardware failures detected.  I've run SupportAssist OS recovery to ensure that I have the factory version of Windows 10.  I cannot get tent mode to work where you flip the screen back on itself and stand the system up on it.  I'm wondering if it is a configuration issue and if so where can I look or if it is indeed a hardware issue, what should I look at?

Thanks!