Do not factor in screen_hsize() for the visible copy mode screen when

adjusting the selection, it should never have any useful history (and
when it does, after resize, we shouldn't use it). From Michal Mazurek.

window-copy.c

@@ -1458,7 +1458,7 @@ window_copy_adjust_selection(struct window_pane *wp, u_int *selx, u_int *sely)
 	}
 
 	*selx = sx;
-	*sely = screen_hsize(s) + sy;
+	*sely = sy;
 	return (relpos);
 }