public void OutdentText() {
// Grab range
var range = Formatter.FindLineBoundries(TextStorage.Value, SelectedRange);
var line = TextStorage.Value.Substring((int)range.Location, (int)range.Length);
// Decrease tab indent
var output = DecreaseTabIndent(line);
// reformat section
TextStorage.BeginEditing();
Replace(range, output);
TextStorage.EndEditing ();
SelectedRange = new NSRange(range.Location, output.Length);
Formatter.HighlightSyntaxRegion(TextStorage.Value, SelectedRange);
}