thin plastic embedded in frame that seems to make things slide easily
A quick learner from Oregon State says:
July 29, 2016
What is it called? It falls out easily. It's very thin and embedded in the frame on the side that slides up and down against the screen frame and the window frame.
Tom from SWISCO responded:
August 2, 2016
I'm sorry, but I don't know what it is you're describing. Could you show me a picture?