Well this is really weird and embarrassing.
I had plugged in another tablet today (Dell VP8) with the adapter and all was good.
The HDMI cable going from the monitor goes into the Display Link adapter and then to the tablet.
After using the DVP8 I went back to my ASUS notebook/tablet.
But I forgot I was still using the DVP8 HDMI cable.
My ASUS HDMI cable goes from the monitor directly to the ASUS.
So I had been bypassing the Display Link altogether.
But it used to display full screen this way before.
Anyhow. Long story short. With the Display Link adapter it is now showing full screen.
I didn't touch any screen setting.
Question:
There is no issue using the Display adapter for both monitor and ethernet connection at the same time?