title: Selecting and replacing a formatted text in UWP RichEditBox with new text is taking the old formatting , i need new text with default formatting
body: <p>Assume I am changing the foreground color of the first five letters to green ,and the default foreground color is black for the REB .</p>
  <pre><code>ITextRange range = Editor.Document.GetRange(0, 4);
  range.CharacterFormat.ForegroundColor = Windows.UI.Colors.Green;
  </code></pre>
  <p>Now if I select this text and replace with a single word , I need new text in black .But REB is retaining the old formatting for that text range and writes in green .</p>