1 files changed, 20 insertions, 8 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index e447211a277..2a7216f3975 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -7871,6 +7871,9 @@ read_key_sequence (keybuf, bufsize, prompt, dont_downcase_last,
   volatile int function_key_possible = 0;
   volatile int key_translation_possible = 0;
 
+  /* List of events for which a fake prefix key has been generated.  */
+  volatile Lisp_Object fake_prefixed_keys = Qnil;
+
   /* Save the status of key translation before each step,
      so that we can restore this after downcasing.  */
   Lisp_Object prev_fkey_map;
@@ -7885,6 +7888,9 @@ read_key_sequence (keybuf, bufsize, prompt, dont_downcase_last,
   int junk;
 #endif
 
+  struct gcpro gcpro1;
+
+  GCPRO1 (fake_prefixed_keys);
   raw_keybuf_count = 0;
 
   last_nonmenu_event = Qnil;
@@ -8117,6 +8123,7 @@ read_key_sequence (keybuf, bufsize, prompt, dont_downcase_last,
           if (EQ (key, Qt))
             {
               unbind_to (count, Qnil);
+              UNGCPRO;
               return -1;
             }
 
@@ -8300,18 +8307,22 @@ read_key_sequence (keybuf, bufsize, prompt, dont_downcase_last,
 
               /* Expand mode-line and scroll-bar events into two events:
                  use posn as a fake prefix key.  */
-              if (SYMBOLP (posn))
+              if (SYMBOLP (posn)
+                  && (NILP (fake_prefixed_keys)
+                      || NILP (Fmemq (key, fake_prefixed_keys))))
                 {
                   if (t + 1 >= bufsize)
                     error ("Key sequence too long");
-                  keybuf[t] = posn;
-                  keybuf[t+1] = key;
-                  mock_input = t + 2;
                   
-                  /* Zap the position in key, so we know that we've
-                     expanded it, and don't try to do so again.  */
-                  POSN_BUFFER_POSN (EVENT_START (key))
-                    = Fcons (posn, Qnil);
+                  keybuf[t]     = posn;
+                  keybuf[t + 1] = key;
+                  mock_input    = t + 2;
+
+                  /* Record that a fake prefix key has been generated
+                     for KEY.  Don't modify the event; this would
+                     prevent proper action when the event is pushed
+                     back tino unread-command-events.  */
+                  fake_prefixed_keys = Fcons (key, fake_prefixed_keys);
 
                   /* If on a mode line string with a local keymap,
                      reconsider the key sequence with that keymap.  */
@@ -8880,6 +8891,7 @@ read_key_sequence (keybuf, bufsize, prompt, dont_downcase_last,
 
   
 
+  UNGCPRO;
   return t;
 }