// from and to ourself, the up event is swallowed by the
// DnD code. So on next non-up event (which means here and
// now) m_lineSelectSingleOnUp should be reset.
// from and to ourself, the up event is swallowed by the
// DnD code. So on next non-up event (which means here and
// now) m_lineSelectSingleOnUp should be reset.