After owning for 3 years I did not know!!

Took me two years to figure it out! When the dealer did our demo, he had to fully extend the awning to access the water heater compartment (or so he said) because the rear arm covered the access door. I had it parked such that I couldn't extend the awning to get to my water heater bypass valves to winterize last fall. That's when I discovered the latch at the bottom that allowed me to move the arm out of the way without extending. I haven't used the awning yet by anchoring to the ground, but I intend to this year. The flimsy bag awning on our popup survived some incredible winds without problems when set up that way (well anchored). I'm not advocating leaving it out in windy conditions though. The only problem I see is that it would increase the time it takes to roll the thing up if a sudden wind whipped up. That's one of reasons I seldom put up awning lights anymore. Two or three minutes can spell the end of an awning.
We got in our first trip of the year last week-end, and we witnessed our first 'awning on top of a camper' episode. Don't want that to be us!