rem: KMHeaderItem( QListViewItem* parent, int msgId, QString key = QString::null, bool openNow=true )
add: KMHeaderItem( QListView* parent, int msgId, QString key = QString::null, bool openNow=true )
context:     KMHeaderItem( QListViewItem* parent, int msgId, QString key = QString::null, bool openNow=true )    : KListViewItem( parent ),	  mMsgId( msgId ),	  mKey(key)  {    irefresh(openNow);  }