ends of each frame member are cut off square where they meet the respective planar surfaces 23 24 25 of the corner fitting 20 fig4 shows a known door end corner fitting 1 as illustrated the fitting is a top fitting but would also be suitable for use at the bottom the fitting 1 is connected to a horizontal frame member 6 and to an upright frame member 7 a part of one door 8 and a small section of a flexible seal 10 engaged with the door are also shown it can be seen that the seal is formed as a 34 j 34 comprising an outer portion 25 and an inner portion 26 the outer portion 25 laps over the door 8 and the adjacent frame member 6 or 7 and the inner portion 26 is pushed into the gap between the door 8 and the adjacent frame member 6 or 7 the seal is typically continuous around the door perimeter and the contact line of the outer lip 25 is denoted by a dotted line 27 to provide a smooth flat surface for the outer seal lip 25 the respective outer faces 28 29 of the frame members.