Complex sentence: Windows Vista also supports "ghosting" of online files and folders, that is, when users make only a few files from a directory available offline, Windows Vista creates ghosted entries of the remaining items to preserve the online context.
Split into simpler sentences: Windows Vista also supports "ghosting" of online files and folders. When users make only a few files from a directory available offline, Windows Vista creates ghosted entries of the remaining items to preserve the online context.