https://learn.microsoft.com/en-us/windows/win32/controls/wm-ctlcoloredit?redirectedfrom=MSDN
WM_CTLCOLOREDIT message (Winuser.h) - Win32 apps | Microsoft Learn
An edit control that is not read-only or disabled sends the WM\_CTLCOLOREDIT message to its parent window when the control is about to be drawn.
wmmessagehappsmicrosoft