We did not like the OEM screen door, slide door. The little door always was left open because you had to slide it open to unlatch the screen or to close the door when connected to the main door. I installed the Lippert Components, Inc - Slider; Screen; Towable W/Knob #239061 & Camco 42183 RV Screen Door Cross Bar . The door panel now has a disc you push down to open screen door. The cross bar is really nice to pull the doors closed.
http://store.lci1.com/slider-screen-towable-wknob-p1404.aspx