Fixed scrolling bug.

diff --git a/controls/listbox.c b/controls/listbox.c
index fa13ba7..eaabe72 100644
--- a/controls/listbox.c
+++ b/controls/listbox.c
@@ -2895,6 +2895,7 @@
 		       }
 		     }
 		     return LISTBOX_HandleLButtonUp( wnd, descr );
+		case WM_LBUTTONDBLCLK:
 		case WM_LBUTTONDOWN:
                      return LISTBOX_HandleLButtonDownCombo(wnd, descr, wParam, 
                                           (INT16)LOWORD(lParam),