Abstract: A break-in resistant window assembly whose components include a window pane having at least a pair of edges and a corner; a frame boarding the window pane; a sheet of polymeric film overlying the pane, a first adhesive layer fixedly interconnecting the pane and the sheet of polymeric film; and a corner assembly which includes a base portion and a cover portion which are able to be mechanically locked to each other to complete a corner assembly. The base portion includes adhesive pads for bonding both to the corner of the window pane and the corner of the window frame. Trim pieces which abut the base portion are also bonded to the window pane and the window frame by adhesive pads. The cover portion is arranged to extend over the abutting ends of the base portion and the trim pieces and thereby conceal any mismatch between those abutting edges.