I recently created a Tag Tree for all my non-People tags.  All the tags are unique, even though I know identical tag names are allowed to exist under different branches of the tree. Then I did an Item→Write Metadata to File, followed by an Item→Reread Metadata from File for a number of images.  The results were a destruction of my tag tree.  The tags that were re-read from the file's metadata, were placed outside the tag tree and the number of images shown existing under the original tree oriented tags were reduced since the new non-tree tag replaced the tree oriented tag.

I understand that this would be a correct behavior under two conditions:
1.  If a new tag never seen before was read from the image file
2. If two or more tags having identical names were in different locations within the tree

However, when reading the metadata tags from an image and each tag name in the image only exists once within the entire tree, then the import of the metadata should honor the tags current location within the tree.  Without this behavior, the use of Tag Trees is useless as it does not have reliable stability as one exports and re-imports metadata tags over the course of time.

In summary: please put imported tags in their currently existing position within a tag tree if the tag name is unique within the entire tree and the tag name is not a new never before seen tag.

Thanks,
Stewart