File's metadata not updated by changes made in Windows Photo Gallery

I am using Windows 7 64 bit and Windows Photo Gallery 2012

In WPG it is possible to change various pieces of metadata such as date taken, tag, caption, subject. This works fine but, certainly for me, does not update metadata on the original file (as seen in Properties/Detail in Windows Explorer). Instead, it seems to add this data to its own WPG metadata database. This means that Explorer and WPG are out of step. it also means that i am worried about what happens if i move to a new computer or if WPG is superceded by other software - will i lose all my changes?

My files are straightforward JPEGs

Is this what is supposed to happen with WPG changes or can you suggest anything that might be wrong with my set-up which is not allowing WPG to update the metadata on the original file?

Something related which might be worth mentioning is that, if I look in Properties/Details while in WPG, most of the data is blank. To be precise, all the data under the headings Description,Origin, Image, Camera and Advanced Photo are blank. The only heading with actual data is File.

I have this same problem but I have not installed Fast Picture Viewer Codec so have no solution at present. Any help would be appreciated.