The specified attributes are used as columns in the search result editor. When specifying + or * then we have to calculate the displayed columns dynamically by fetching all attribute types from all search result entries. There could be a large number of displayed columns so we have to enable horizontal scrolling for the search result editor.
When we change the attribute selection we could also add the "Requesting Attributes by Object Class" extension (http://rfc.net/rfc4529.html). Then you could just request "@person" to get all attributes of objectclass person.