internal ids are changing

[dieterdreist]

I don't know whether this is expected, but I didn't, somehow I experience the ids in saved files changing. It doesn't happen always, and I am not sure which operation makes them shift, but I can see it in the files (it is the same file, save consecutively):

 % head local_005.osm
<?xml version='1.0' encoding='UTF-8'?>
<osm version='0.6' upload='false' generator='JOSM'>
  <node id='-1587743' lat='45.80836512471' lon='7.27175232872' />
  <node id='-1587744' lat='45.80846685784' lon='7.2716349593' />
  <node id='-1587745' lat='45.8085647' lon='7.27155792816' />
  <node id='-1587746' lat='45.80856694459' lon='7.27170626972' />
  <node id='-1587747' lat='45.8086692203' lon='7.27241995035' />
  <node id='-1587748' lat='45.80877815765' lon='7.27173320596' />
  <node id='-1587749' lat='45.80899113177' lon='7.27155602427' />
  <node id='-1587750' lat='45.80924687428' lon='7.27166994302' />

 % head local_006.osm
<?xml version='1.0' encoding='UTF-8'?>
<osm version='0.6' upload='false' generator='JOSM'>
  <node id='-1756958' lat='45.80836512471' lon='7.27175232872' />
  <node id='-1756959' lat='45.80846685784' lon='7.2716349593' />
  <node id='-1756960' lat='45.8085647' lon='7.27155792816' />
  <node id='-1756961' lat='45.80856694459' lon='7.27170626972' />
  <node id='-1756962' lat='45.8086692203' lon='7.27241995035' />
  <node id='-1756963' lat='45.80877815765' lon='7.27173320596' />
  <node id='-1756964' lat='45.80899113177' lon='7.27155602427' />
  <node id='-1756965' lat='45.80924687428' lon='7.27166994302' />

 % head local_007.osm
<?xml version='1.0' encoding='UTF-8'?>
<osm version='0.6' upload='false' generator='JOSM'>
  <node id='-1933515' lat='45.80836512471' lon='7.27175232872' />
  <node id='-1933516' lat='45.80846685784' lon='7.2716349593' />
  <node id='-1933517' lat='45.8085647' lon='7.27155792816' />
  <node id='-1933518' lat='45.80856694459' lon='7.27170626972' />
  <node id='-1933519' lat='45.8086692203' lon='7.27241995035' />
  <node id='-1933520' lat='45.80877815765' lon='7.27173320596' />
  <node id='-1933521' lat='45.80899113177' lon='7.27155602427' />
  <node id='-1933522' lat='45.80924687428' lon='7.27166994302' />