OK, I think I've got to the bottom of what may be going on.
Bjørn Tore reported that on his system, WLPG *does* watch folders and keep
Tags in sync with changes made by other metadata editors. As a result, I've
been looking again and found the following:
1) some of my image files *do* trigger WLPG to update its Tag list; other
files don't.
2) All the files are JPEGs - so the reason for the difference is not the
file format.
3) For some files, the list of Tags (Keywords) for a file that is displayed
in WLPG and the Vista Windows Explorer is *different* from the list of IPTC
Core for XMP Keywords for the file. These are supposed to be the same.
4) As far as I can see, these are the files that fail to trigger a WLPG
update, when the IPTC Core for XMP Keywords are modified outside of WLPG.
My suspicion is that somewhere along the line, the XMP metadata used by
Microsoft for WLPG has got out of step with the XMP metadata used by the
IPTC Core schema on those files. Then, even though IPTC Core for XMP
metadata was changed, WLPG would not pick it up if it first checks its
internal XMP structures (and assumes that these are always in synch with
IPTC Core metadata.
I had to force a change on WLPG tags to trigger a resync between my workflow
tools. Hopefully, these will now continue in sync.
Geoff Coupe
http://gcoupe.spaces.live.com/ - the Blog
http://flickr.com/photos/gcoupe - the Photos
http://www.librarything.com/catalog/gcoupe - the Library