Disposal of sub

In the case of complete disposal of a subsidiary, do we reclassify all the gains/losses held in OCI at the disposal date? if yes, then why are items meant not to be reclassified are reclassified? this is from the technical article of Acca: Reclassify to profit or loss any amounts (the entire amount, not a proportion) relating to the subsidiary’s assets and liabilities previously recognised in other comprehensive income, as if the assets and liabilities had been disposed of directly.