The button to press is visible behind the cord, just press it in with a screwdriver and pull the frame outwards.

https://www.dropbox.com/s/jslfr5plw3...05.30.jpg?dl=0

Once all the clips on one side are released then the frame can be removed.

View of clip removed from window, the short bend is the part hooked between glass and beading.

https://www.dropbox.com/s/hjg481isuq...06.10.jpg?dl=0

Richard