A corner connector (10) for connecting adjacent first and second spacer sections (20, 22), to form an insulated panel spacer frame includes a first arm (12) joined by a flexible joint (15) to a second arm (14). The second arm includes a recess (44) adjacent the joint, and a deformable projection (46) projecting from an edge of the open face of the recess inwardly toward the bottom of the recess. The first arm includes a securement projection (38) protruding from adjacent the joint (15) that is receivable within the recess of the second arm alongside the deformable projection. The deformable projection is deformed by the securement projection and exerts a compressive force on the securement projection to releasably secure the first and second arms in a desired angular orientation.