private void GetCompositionPositions(UnsafeNativeMethods.ITfCompositionView view, out ITextPointer start, out ITextPointer end)
{
UnsafeNativeMethods.ITfRange range;
view.GetRange(out range);
TextPositionsFromITfRange(range, out start, out end);
Marshal.ReleaseComObject(range);
Marshal.ReleaseComObject(view);
}