internal void Replace(int offset, int length, string text)
{
// foreach (ISelection selection in selectionCollection) {
// if (selection.Offset > offset) {
// selection.Offset = selection.Offset - length + text.Length;
// } else if (selection.Offset + selection.Length > offset) {
// selection.Length = selection.Length - length + text.Length;
// }
// }
}