Does it make sense to restrict movement of a TAG and TAG-Group together, while they can be moved individually in Photoshop Elements?

(Old post migrated from other blog) I use Keyword Tags in Organizer of Adobe Photoshop Elements and they are very useful for me from organizing and SEO point of view. Slowly Tag heirarchy in my catalog increased and thought of regrouping my Tags. During this, I came across this weird behavior - I was able to move single Tag and Single Tag-Group, but when tried to move one Tag & Tag-group together, it was not allowed.

Let me explain with example -

TGs are Tag-Groups...

Ts are Tags...

TG-A

   -  TGAA

          - T-AAA

          - T-AAAA

   - TGAA1

          - T-AAA1

          - T-AAAA1

          - T-AAAAA1

   - T-A2

   - T-A3

TG-B

Now if I want to move Tag T-A2 under TG-B, I can do it and same for Tag-Group TGAA. But I select Tag T-A2 and TGAA, movement is not allowed under TG-B.

I really got frustrated as it doesn't sound logical to me and I had lot of Tags to handle. Do you think, it makes sense for any reason you can think of?