// Listening the mouseDown and mouseUp events in the TaskItemTemplate

<fxgantt:FlexyGantt.TaskItemTemplate>

     <DataTemplate>

          <Grid PreviewMouseLeftButtonDown="Grid_PreviewMouseLeftButtonDown" PreviewMouseLeftButtonUp="Grid_PreviewMouseLeftButtonUp" Height="18">

                .....................

                 ..............

           </Grid>

      </DataTemplate>

</fxgantt:FlexyGantt.TaskItemTemplate>

Point mouseDownPt;

private void Grid_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)

{

    mouseDownPt = e.GetPosition(this);

}

private void Grid_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)

{

    Point mouseUpPt = e.GetPosition(this);

    if (mouseUpPt == mouseDownPt)

    {

         // Mouse Click event code goes here.

    }

}