private void ClearHighlighting()
{
var selectedRange = InputTextBox.Selection;
var visibleRange = InputTextBox.VisibleRange;
var firstVisibleLine = Math.Min(visibleRange.Start.iLine, visibleRange.End.iLine);
var txt = InputTextBox.Text;
InputTextBox.Clear();
InputTextBox.Text = txt; //remove all old highlighting
InputTextBox.SetVisibleState(firstVisibleLine, FastColoredTextBoxNS.VisibleState.Visible);
InputTextBox.Selection = selectedRange;
}