if DBGrid2.SelectedField.FieldName = FEditor.DataField then...

DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
  DataCol: Integer; Column: TColumn; State: TGridDrawState);

void __fastcall TForm_Main::DBGrid_DealsDrawColumnCell(TObject *Sender,
      const TRect &Rect, int DataCol, TColumn *Column,
      TGridDrawState State)
{
    int where_space = Column->Title->Caption.Pos(" ");
    int H = DBGrid_Deals->Canvas->TextHeight("gW");
    int RH = (H + 2) * 2;
    ((TMyAccessGrid*)DBGrid_Deals)->RowHeights[0] = RH;
    TRect ARect;
    SetRect(&ARect, Rect.Left, 0, Rect.Right, RH);
    InflateRect(&ARect,-2,-2);
    DBGrid_Deals->Canvas->Brush->Color = clBtnFace;
    DBGrid_Deals->Canvas->FillRect(ARect);
    if(where_space==0)
    {
        ::DrawText(DBGrid_Deals->Canvas->Handle,Column->Title->Caption.c_str(),
            -1,&ARect,DT_CENTER | DT_SINGLELINE | DT_VCENTER );
    }
    else
    {
        AnsiString as = Column->Title->Caption;
        ::DrawText(DBGrid_Deals->Canvas->Handle,
                as.SubString(0,where_space).c_str(),
            -1,&ARect,DT_CENTER | DT_SINGLELINE );
            
        ARect.top+=H;
        ::DrawText(DBGrid_Deals->Canvas->Handle,
                as.SubString(where_space+1,as.Length()).c_str(),
            -1,&ARect,DT_CENTER | DT_SINGLELINE );
    }

  
type
  TForm1 = class(TForm)
.......
  private
.......
    FOldDbGridWndProc : Pointer; // старая оконная процедура DBGrid'а
    procedure NewDbGridWndProc (var Message : TMessage); // Новая оконная процедура
                                                   // для DBGrid'а

procedure TForm1.NewDbGridWndProc(var Message: TMessage);
begin
  case Message.Msg of
  WM_HSCROLL:
    begin
      InvalidateRect(DBGrid.Handle, nil, true);
      FEditor.Visible := false;
    end;
  end;
  with Message do
    Result := CallWindowProc(FOldDbGridWndProc, DBGrid.Handle, Msg, wParam, lParam);
end;

procedure TForm1.FormShow(Sender: TObject);
begin
  FOldDbGridWndProc := Pointer(GetWindowLong(DBGrid.Handle, GWL_WNDPROC));
  SetWindowLong(DBGrid.Handle, GWL_WNDPROC,
    Integer(MakeObjectInstance(NewDbGridWndProc)));
end;

 Игорь Шевченко

void __fastcall TForm1::DBGrid4DrawColumnCell(TObject *Sender,
      const TRect &Rect, int DataCol, TColumn *Column,
      TGridDrawState State)
{
  if(State.Contains(gdFocused))
  {
   if(Column->Field->FieldName==FEditor->DataField)
   {
      FEditor->Left = Rect.Left + DBGrid4->Left;
      FEditor->Top = Rect.Top + DBGrid4->Top;
      FEditor->Width = Rect.Right - Rect.Left + 2;
      FEditor->Visible = true;
      return;
   }
    if(Column->Field->FieldName==FEditor12->DataField)
   {
      FEditor12->Left = Rect.Left + DBGrid4->Left;
      FEditor12->Top = Rect.Top + DBGrid4->Top;
      FEditor12->Width = Rect.Right - Rect.Left + 2;
      FEditor12->Visible = true;
   }
   }
}

void __fastcall TForm1::DBGrid4ColExit(TObject *Sender)
{
if (DBGrid4->SelectedField->FieldName == FEditor->DataField)
{
    FEditor->Visible = false;
     return;
    }
  if (DBGrid4->SelectedField->FieldName == FEditor12->DataField)
{
    FEditor12->Visible = false;
    }
}

TexDBGrid = class(TDBGrid)
private
...
  FMouseWheelUp : TNotifyEvent;
  FMouseWheelDown : TNotifyEvent;
...
published
...
  property OnMoseWheelUp: TNotifyEvent read FMouseWheelUp write FMouseWheelUp;
  property OnMoseWheelDown: TNotifyEvent read FMouseWheelDown write FMouseWheelDown;
...
protected
...
  function DoMouseWheelDown(Shift: TShiftState; MousePos: TPoint): Boolean; override;
  function DoMouseWheelUp(Shift: TShiftState; MousePos: TPoint): Boolean; override;
...
...
...

function TexDBGrid.DoMouseWheelDown(Shift: TShiftState; MousePos: TPoint): Boolean;
begin
  if Assigned(FMouseWheelDown)
    then FMouseWheelDown(Self)
    else if (Assigned(DataSource)) and (not DataSource.DataSet.Eof)
      then DataSource.DataSet.Next;
  result := true;
end;

function TexDBGrid.DoMouseWheelUp(Shift: TShiftState; MousePos: TPoint): Boolean;
begin
  if Assigned(FMouseWheelUp)
    then FMouseWheelUp(Self)
    else if (Assigned(DataSource)) and (not DataSource.DataSet.Bof)
      then DataSource.DataSet.Prior;
  result := true;
end;

...
...

    procedure DBGrid1KeyUp
     if ((Key=Key_F2)or
       (Key=Key_Return)or
       (Key=Key_Enter))and
       (DBGrid1.InplaceEditor.Visible)

    procedure DBGrid1MouseUp
     if DBGrid11.InplaceEditor.Visible