diff --git a/diff_edit/__init__.py b/diff_edit/__init__.py
index 083bab3..96e413f 100755
--- a/diff_edit/__init__.py
+++ b/diff_edit/__init__.py
@@ -209,7 +209,8 @@ class DiffEditor:
                     right_start, right_end, left_start, left_end
             if left_start <= y < left_end:
                 fraction = (y - left_start) / (left_end - left_start)
-                return round(right_start + fraction * (right_end - right_start))
+                other_y = round(right_start + fraction * (right_end - right_start))
+                return other_y - 1 if other_y == len(self.editors[1].text_widget) else other_y
         return 0
 
     def follow_scroll(self):
diff --git a/diff_edit/editor.py b/diff_edit/editor.py
index b284f20..8068c76 100755
--- a/diff_edit/editor.py
+++ b/diff_edit/editor.py
@@ -263,8 +263,9 @@ class Editor:
         if not self.is_editing:
             return result
         if self.mark is None:
-            result[self.cursor_y - view_y] = highlight_str(result[self.cursor_y - view_y],
-                                                           termstr.Color.white, 0.8)
+            with contextlib.suppress(IndexError):  # Fix. The cursor should always be on screen.
+                result[self.cursor_y - view_y] = highlight_str(result[self.cursor_y - view_y],
+                                                               termstr.Color.white, 0.8)
         else:
             (start_x, start_y), (end_x, end_y) = self.get_selection_interval()
             screen_start_x = len(expand_str(self.text_widget[start_y][:start_x]))