The key specified by idKey will be removed from the management in the Flat. Calling ⇘ MBM.FlatTest now always will return bEnabled = FALSE. The value which had been valid before calling the function will be returned in hOldMsg and should be deallocated afterwards via MBM.MsgRelease. If up to now no value has been entered in the Flat, CAA.gc_hINVALID will be returned.