X1 = 0; X2 = twGetClientWidth(MainWnd); Y1 = 1; Y2 = twGetClientHeight(MainWnd) - 1;

                      TWindow *wnd =

                              MainWnd ? MainWnd :  /*XXX:drop this line?*/

                              twGetWinAtPos(mx, my);

                      if(!wnd) return KE_MOUSE;

                      X1 = 0; X2 = twGetClientWidth(wnd); Y1 = 1; Y2 = twGetClientHeight(wnd) - 1;