The tail gate on my truck is about 1/2 inch too wide. It hits my electric jack on the trailer A-frame. I found if the truck-trailer is parked on a hill in such a way the combination forms a /\ configuration insead of -- or even \/ the tail gate will open all the way.
So, what I started doing was to simply lower the electric jack while hitched, thus raising the tongue of the trailer. Attached to the truck, the end of the ruck raises with the trailer, causing a /\ configuration between truck and trailer. Once the jack raises the A-frame of the trailer and the end of the truck high enough, the tail gate lays flat and misses the electric jack.
Since the jack is electric, it's really an easy alternative. (Just remember to close the tail gate before retracting the jack or before pulling forward with the truck!) But this does work.