Abstract: A hopper-type window sash movable from a closed position within an opening in a frame to an open position in which the sash extends at an angle from one edge located in the frame opening. Hardware includes a pivot slide supporting such one edge of the sash for pivotal and sliding movement along integral tracks provided in the frame. Opposed control assemblies each include a frame pivot member directly mounted in an associated track and a sash pivot member directly mounted on the sash. A thin control strap is pivoted at one end on the frame pivot member, and at its other end on the sash pivot member. One pivot is releasable to allow easy access for mounting all hardware while the sash and frame are separated. The control strap moves through a narrow opening between the sash and frame, permitting multiple seals to effectively seal the window.