private void ActivityTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
//http://stackoverflow.com/questions/1895204/textbox-scrolltoend-doesnt-work-when-the-textbox-is-in-a-non-active-tab
// microsoft scrolling issue that when you focus on the textbox, scroll up,
// it's no longer scroll to end even when u call the function
// use the workaround
ActivityTextBox.CaretIndex = ActivityTextBox.Text.Length;
ActivityTextBox.ScrollToEnd();
}
