diff --git a/src/edit.c b/src/edit.c
index fb347b8..9caca85 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -8597,7 +8597,12 @@
     tpos = curwin->w_cursor;
     if (oneleft() == OK)
     {
-	start_arrow(&tpos);
+#if defined(FEAT_XIM) && defined(FEAT_GUI_GTK)
+	/* Only call start_arrow() when not busy with preediting, it will
+	 * break undo.  K_LEFT is inserted in im_correct_cursor(). */
+	if (!im_is_preediting())
+#endif
+	    start_arrow(&tpos);
 #ifdef FEAT_RIGHTLEFT
 	/* If exit reversed string, position is fixed */
 	if (revins_scol != -1 && (int)curwin->w_cursor.col >= revins_scol)