It's the simple things that are often overlooked, even by qualified experts. Don't worry, you paid (included in the initial cost of the windows) for those service calls.......The folks who installed our windows when we remodeled our houses just sent out a service man for the 5th time in the last year and a half to fix our bathroom window. It seems that someone had a couple of clip things on backwards which would not allow the window to fully close. Took them a year and a half and 5 different trips out here to fix the window to discover this. It works now and I am glad. I'm scratching my head and wondering how they can stay in business if their service is no better than this though?????????