The subject assembly is intended for use in selectively closing in balconies and is made up of an upper guide, a lower guide and several panel subassemblies. The upper guide is attached to the ceiling of the balcony and the lower guide to the floor or top of the railing. Each panel subassembly is made up of a rectangular glass panel, an upper fitting attached to its upper edge, and a lower fitting attached to its lower edge. One guide fitting and one pivoted guide fitting assembly are attached to the upper fitting and two guide fitting assemblies, one pivoted, are attached to the lower fitting. The guide fitting and fitting assemblies slide in the guides. The pivoted guide fitting assemblies allow the subassemblies to pivot about an axis near one vertical edge. A roller is attached to each guide fitting assembly on the lower fitting and the rollers carry the weight of the panel subassemblies. One panel subassembly is permanently positioned at the retracted end of the guides. To retract the assembly the permanently positioned subassembly is opened and the others are sequentially moved to the retracted end and opened. The upper guide fitting assemblies are engaged by a leaf spring to lock the subassemblies in the retracted position. During assembly extension, as each subassembly is turned to re-engage the guides, a cam on the upper guide fitting assembly engages the end of the spring to unlock the subassembly. The lock springs are attached to the inner surface of the outer flange of the upper guide.