diff --git a/src/undo.c b/src/undo.c
index 62963a9..792d791 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -2984,7 +2984,7 @@
     if (curbuf->b_u_synced || (!force && no_u_sync > 0))
 	return;
 #if defined(FEAT_XIM) && defined(FEAT_GUI_GTK)
-    if (im_is_preediting())
+    if (p_imst == IM_ON_THE_SPOT && im_is_preediting())
 	return;		    /* XIM is busy, don't break an undo sequence */
 #endif
     if (get_undolevel() < 0)