Abstract: An improved retainer element has a mounting section which is connected with a rim portion of a panel. A longitudinally extending main spring section of the retainer element extends from the mounting section. A retainer section of the retainer element is connected with an end of the main spring section opposite from the mounting section. The retainer section includes a retainer flange and a pair of retainer arms which engage opposite sides of the rim portion of the panel. When the panel is moved into position relative to the support frame, a cam surface on the retainer flange engages the support frame and transmits force to deflect the main spring section of the retainer element. The retainer flange then snaps into engagement with the support frame. The retainer arms slide along opposite side surfaces of the rim portion of the panel to guide movement of the main spring section relative to the panel.