http://lists.gnu.org/archive/html/nano-devel/2006-01/msg00000.html
http://lists.gnu.org/archive/html/nano-devel/2006-01/msg00001.html

diff -ur nano-1.3.10/src/winio.c nano-1.3.10-fixed/src/winio.c
--- nano-1.3.10/src/winio.c	2005-12-08 02:24:54.000000000 -0500
+++ nano-1.3.10-fixed/src/winio.c	2006-01-10 03:10:14.000000000 -0500
@@ -2772,6 +2772,11 @@
 
 	openfile->edittop = old_edittop;
 
+	/* Update old_current if we're not on the first page and/or
+	 * we're not on the same page as before. */
+	if (do_redraw)
+	    update_line(old_current, 0);
+
 	/* Scroll the edit window up or down until edittop is in range
 	 * of current. */
 	if (nlines < 0)