Dometic will advise you NOT to lock those arms. Their design, (which I detest!), is to allow the awning to move about in the wind. Those pneumatic rods are supposed to return the awning to the proper position.
How do I know this? Close to $500.00 to replace the tubes. A gust of wind hit the awning while I had the arms locked. No flex .... except the arm it's self, which committed suicide.
"IF" you choose to lock them, then you MUST tie them down to prevent movement.
As to the original question, on my Windjammer the door also drags the bottom of the awning. If I ever have to mess with it again, I will replace it with a manual awning.
2017 Windjammer 3029W
2006 Ford F-150
HD 7700# tow package