By the late 1970s, DON MILLS CENTRE has been enclosed and climate-controlled. Its South Wing was fully realized in the mid-1960s (in dark gray). The Eaton's store was also enlarged. As part of the  enclosing renovation, open areas were filled with new store space (in light gray). The mall now encompasses over 400,000 leasable square feet.

A circa-1980 view of the new interior mall of DON MILLS CENTRE.
Photo from https://www.blogto.com / BlogTO / Toronto Archives

Since 1968, DON MILLS CENTRE had been owned by the Fairview (later Cadillac Fairview) Corporation. Their most prestigious Metro Toronto property, FAIRVIEW MALL, opened in 1970. Although both complexes were owned by the same company, FAIRVIEW MALL was still a major rival of DON MILLS CENTRE.

Photo from Wikipedia / "GTD Aquitaine"