private void RemoveLine(DocumentLine lineToRemove)
{
foreach (var lt in lineTrackers)
lt.BeforeRemoveLine(lineToRemove);
documentLineTree.RemoveLine(lineToRemove);
// foreach (ILineTracker lt in lineTracker)
// lt.AfterRemoveLine(lineToRemove);
// deletedLines.Add(lineToRemove);
// deletedOrChangedLines.Add(lineToRemove);
}