The Income Tax Act indicates that if a corporate's tax return is filed 3 years after the return was to be filed, no dividend refund is allowed.  The CRA was denying the claim for the refund for future years.  Two recent court cases have indicated that the dividend refund can be carried forward to subsequent years.  No refund is received for the years filed late but the RDTOH balance remains intact. 

http://decision.tcc-cci.gc.ca/tcc-cci/decisions/en/item/109098/index.do?r=AAAAAQAGbmFuaWNhAQ