patch 8.0.0043
Problem:    When using Insert mode completion with 'completeopt' containing
            "noinsert" with CTRL-N the change is not saved for undo.  (Tommy
            Allen)
Solution:   Call stop_arrow() before inserting for any key.
diff --git a/src/edit.c b/src/edit.c
index 776a420..3a0e188 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -4634,14 +4634,19 @@
     static void
 ins_compl_delete(void)
 {
-    int	    i;
+    int	    col;
 
     /*
      * In insert mode: Delete the typed part.
      * In replace mode: Put the old characters back, if any.
      */
-    i = compl_col + (compl_cont_status & CONT_ADDING ? compl_length : 0);
-    backspace_until_column(i);
+    col = compl_col + (compl_cont_status & CONT_ADDING ? compl_length : 0);
+    if ((int)curwin->w_cursor.col > col)
+    {
+	if (stop_arrow() == FAIL)
+	    return;
+	backspace_until_column(col);
+    }
 
     /* TODO: is this sufficient for redrawing?  Redrawing everything causes
      * flicker, thus we can't do that. */
@@ -5059,8 +5064,11 @@
     colnr_T	curs_col;	    /* cursor column */
     int		n;
     int		save_w_wrow;
+    int		insert_match;
 
     compl_direction = ins_compl_key2dir(c);
+    insert_match = ins_compl_use_match(c);
+
     if (!compl_started)
     {
 	/* First time we hit ^N or ^P (in a row, I mean) */
@@ -5486,6 +5494,8 @@
 	edit_submode_extra = NULL;
 	out_flush();
     }
+    else if (insert_match && stop_arrow() == FAIL)
+	return FAIL;
 
     compl_shown_match = compl_curr_match;
     compl_shows_dir = compl_direction;
@@ -5494,8 +5504,7 @@
      * Find next match (and following matches).
      */
     save_w_wrow = curwin->w_wrow;
-    n = ins_compl_next(TRUE, ins_compl_key2count(c),
-						ins_compl_use_match(c), FALSE);
+    n = ins_compl_next(TRUE, ins_compl_key2count(c), insert_match, FALSE);
 
     /* may undisplay the popup menu */
     ins_compl_upd_pum();
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index d037b7a..cc93ff8 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -427,6 +427,11 @@
   call feedkeys("u", 'xt')
   call assert_equal('bbb', getline(2))
 
+  call feedkeys("A\<Right>\<C-N>\<Esc>", 'xt')
+  call assert_equal('January', getline(2))
+  call feedkeys("u", 'xt')
+  call assert_equal('bbb', getline(2))
+
   iunmap <Right>
   set completeopt&
   q!
diff --git a/src/version.c b/src/version.c
index 3a2b1a5..e910845 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    43,
+/**/
     42,
 /**/
     41,