Related smells: Divergent Change, Spaghetti Code
Nonterminals that refer to one another, should be located close to one another. The longer the distance between the use of a nonterminal from its definition, the more the reader of the grammar will have to switch context. A lot of scrolling always means there is something smelly about how the grammar is set up. Moving the production rules that cause the scrolling closer to each other to form a cluster, will result in an easier grammar with more coherent structure.
Automated removal of this smell is problematic, since the grammar engineer should decide which nonterminals to move where, but there are a lot of heuristics one can develop and test their effectiveness empirically.