If you want to color an edit control for instance,
you'll have to process the WM_CTLCOLOREDIT message in the PARENT window procedure:

Note that a read-only or disabled edit control will send an WM_CTLCOLORSTATIC.

//Global scope
 COLORREF bkgCol = RGB(128, 128, 128);
 HBRUSH br = CreateSolidBrush(bkgCol);

 case WM_CTLCOLOREDIT:
  SetBkColor((HDC)wParam, bkgCol);
  SetTextColor((HDC)wParam, RGB(0, 255, 0));
 return ((LRESULT)br);

//Uppon destroy of window:
 DeleteObject(br);

All controls color messages:
WM_CTLCOLOREDIT
WM_CTLCOLORBTN
WM_CTLCOLORDLG
WM_CTLCOLORLISTBOX
WM_CTLCOLORMSGBOX
WM_CTLCOLORSTATIC