The sleeping babies are adorable.
and
The babies sleeping are adorable.
To me, the two sentences are identical in meaning. However, this doesn't seem to be the case in the following sentence:
The singing sensation is a teen heart throb.
and
The sensation singing is a teen heart throb.
To me, the subject of the first sentence is a singer whereas the subject of the second sentence is in the process of singing.
Is there a rule for when using a present participle as an adjective does not carry the same meaning as doing a whiz deletion?