commit https://github.com/vim/vim/commit/00672e1d3f59dbff91a18d418b2984be96f89ee5 Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jun 26 18:38:13 2016 +0200 patch 7.4.1961 Problem: When 'insertmode' is reset while doing completion the popup menu remains even though Vim is in Normal mode. Solution: Ignore stop_insert_mode when the popup menu is visible. Don't set stop_insert_mode when 'insertmode' was already off. (Christian Brabandt)

--- a/src/edit.c
+++ b/src/edit.c
@@ -649,7 +649,11 @@ edit(
 	if (update_Insstart_orig)
 	    Insstart_orig = Insstart;
 
-	if (stop_insert_mode)
+	if (stop_insert_mode
+#ifdef FEAT_INS_EXPAND
+		&& !pum_visible()
+#endif
+		)
 	{
 	    /* ":stopinsert" used or 'insertmode' reset */
 	    count = 0;