private void TextArea_MarginClick(object sender, ScintillaNET.MarginClickEventArgs e) { if (e.Margin == BOOKMARK_MARGIN) { // Do we have a marker for this line? const uint mask = (1 << BOOKMARK_MARKER); var line = TextArea.Lines[TextArea.LineFromPosition(e.Position)]; if ((line.MarkerGet() & mask) > 0) { // Remove existing bookmark line.MarkerDelete(BOOKMARK_MARKER); } else { // Add bookmark line.MarkerAdd(BOOKMARK_MARKER); } } }