}
     //
     // There is no return value for the CBN_ notifications, so always return
-    // FALSE from here to pass the message to DefWindowProc()
+    // false from here to pass the message to DefWindowProc()
     //
-    return FALSE;
+    return false;
 } // end of wxComboBox::OS2Command
 
 bool wxComboBox::Create(
 , const wxString&                   rsName
 )
 {
-    m_isShown = FALSE;
+    m_isShown = false;
 
     if (!CreateControl( pParent
                        ,vId
                        ,rValidator
                        ,rsName
                       ))
-        return FALSE;
+        return false;
 
     //
     // Get the right style
     if (!OS2CreateControl( "COMBOBOX"
                           ,lSstyle
                          ))
-        return FALSE;
+        return false;
 
     //
     // A choice/combobox normally has a white background (or other, depending
             ,rSize.x
             ,rSize.y
            );
-    if (!rsValue.IsEmpty())
+    if (!rsValue.empty())
     {
         SetValue(rsValue);
     }
                                                     ,(PFNWP)wxComboEditWndProc
                                                    );
     ::WinSetWindowULong(GetHwnd(), QWL_USER, (ULONG)this);
-    Show(TRUE);
-    return TRUE;
+    Show(true);
+    return true;
 } // end of wxComboBox::Create
 
 void wxComboBox::SetValue(
 
 void wxComboBox::SetInsertionPointEnd()
 {
-    long                            lPos = GetLastPosition();
+    wxTextPos                       lPos = GetLastPosition();
 
     SetInsertionPoint(lPos);
 } // end of wxComboBox::SetInsertionPointEnd
    return lPos;
 } // end of wxComboBox::GetInsertionPoint
 
-long wxComboBox::GetLastPosition() const
+wxTextPos wxComboBox::GetLastPosition() const
 {
     long                            lLineLength = 0L;
     WNDPARAMS                       vParams;
 
     //
     // If from and to are both -1, it means
-    // (in wxWindows) that all text should be selected.
+    // (in wxWidgets) that all text should be selected.
     // This translates into Windows convention
     //
     if ((lFrom == -1L) && (lTo == -1L))
                 case KC_CHAR:
                     return (HandleChar( wParam
                                        ,lParam
-                                       ,TRUE /* isASCII */
+                                       ,true /* isASCII */
                                       ));
 
                 case KC_PREVDOWN:
                 return(HandleKillFocus((WXHWND)(HWND)wParam));
             break;
     }
-    return FALSE;
+    return false;
 } // end of WinGuiBase_CComboBox::ProcessEditMsg
 
 MRESULT EXPENTRY wxComboEditWndProc(
 , MPARAM                            lParam
 )
 {
-    HWND                            hWndCombo;
-    wxWindow*                       pWin = NULL;
-
-    hWndCombo = ::WinQueryWindow(hWnd, QW_PARENT);
-    pWin = (wxWindow*)wxFindWinFromHandle((WXHWND)hWndCombo);
     switch (uMessage)
     {
         //
         case WM_SETFOCUS:
         case WM_CHAR:
             {
-                wxComboBox*         pCombo = wxDynamicCast( pWin
-                                                           ,wxComboBox
-                                                          );
+                wxComboBox* pCombo = (wxComboBox *)::WinQueryWindowULong( hWnd
+                                                                         ,QWL_USER
+                                                                        );
 
                 if (pCombo->ProcessEditMsg( uMessage
                                            ,wParam