SfChart DoughnutSeries Title custom

Hi,
First, I am using Doughnutseries of chart like picture below. As you see the all chart titles overlap. So all title are not readin. How can i solve this problem.
Secondly, I want to do not change SelectedDataPointColor. namely  whatever the color before select, should be same color after select.

<chart:PieSeries ItemsSource="{Binding Data}"                                                               XBindingPath="Expense"                                                               YBindingPath="Value"                                                                StartAngle="75"                                                               EndAngle ="435"                                                               EnableSmartLabels="True"                                                               ConnectorLineType = "Bezier"                                                                DataMarkerPosition = "OutsideExtended">  ..

private void chart_SelectionChanging(object sender, ChartSelectionChangingEventArgs e)  {      e.Cancel = true;  }

Thank you very much for your answers. I have solved both of  :)