The multi-line entry field control window procedure responds to this message by setting the enable state and by setting ulReserved to 0.

Disabling the window is similar, but not identical, to MLM_DISABLEREFRESH. Enabling the window is similar, but not identical, to MLM_ENABLEREFRESH. (Note that this also applies to window styles.) The difference is that a disabled window receives no mouse or keyboard input whereas with MLM_DISABLEREFRESH it receives the input but discards it.