Windows 2000 service pack 2

Using Win2000 pro service pack 2, I’ve noticed an odd behavior of Search when seaching for Files: If, for example, i search for all *.DOC files containing the text “foobar” and one or more documents with that text happen to be open, those documents will not be found/reported in the Search result. Can you confirm this? If so, is this a documented bug? or is this a “feature”?