GetDlgItemIDC_SOURCE_1-EnableWindowFALSE;

This code disables the window associated with the control with ID IDC_SOURCE_1. It is typically used in MFC (Microsoft Foundation Class) applications to disable a specific control based on certain conditions or user actions.

The EnableWindow(FALSE) function is a member function of the CWnd class in MFC. It sets the enabled state of the window associated with the control to FALSE, which means the control is disabled and cannot be interacted with by the user. The opposite function, EnableWindow(TRUE), can be used to enable the control again