Always learning new things about the Barth, and here's todays tidbit.
The screen in the dining window has always been loose, falling out often on rough roads etc. Today I discovered there are little slides in the groove of the screen that act as spacers to tighten up the screen frame onto the window frame. If these slide to the front or back the area where they are supposed to be will not have enough tension in the groove to hold the screen in place. If you slide all 3 on the top and the bottom all the way forward, the screen easily fits in the back, then slide them back to insert the front, then spread them out 1 front 1 middle 1 rear, top and bottom, and the screen will be nice and tight. No more duck tape!

Who is the manufacturer of your windows?

bill, I have no idea. I can't find markings of any kind. The inner frame has lots of screws that hold it to the glazed outer frame, and when you remove all the screws the window comes out. I just resealed the rear bedroom ones and trimmed the insides with wood. Much better looking now.

Mine are Hehr and are the same way.