On our 2007 Itasca Navion, the designer got fancy with the window above the kitchen counter: it's a top-pivot window, activated by a little worm drive-and-gear arrangement. Clever, except the worm shaft runs on one bearing, which, when it wears, results in the worm not engaging the gear. It now won't open without a lot of fussing, and also doesn't close entirely. On a recent trip to the Palm Springs area, which included a couple of very windy nights, the shade was rattling constantly as wind blew through the gap.
I've thought about solutions, but am now considering just replacing the window. If I do, I'm inclined toward a sliding window: simple, more reliable.
Searching on "custom RV window" offers me lots of sources (some of which, from the pictures on the websites, use the same actual manufacturer). I'd appreciate any recommendations from experience of a good, not obscenely expensive, supplier.