/**
* Tell the edits in the given range (inclusive) to die, and
* remove them from edits. from > to is a no-op.
*/
protected void TrimEdits(int from, int to)
{
if (from <= to)
{
for (int i = to; from <= i; i--)
{
IUndoableEdit e = edits[i];
e.Die();
edits.RemoveAt(i);
}
if (indexOfNextAdd > to)
{
indexOfNextAdd -= to - from + 1;
}
else if (indexOfNextAdd >= from)
{
indexOfNextAdd = from;
}
}
}