diff --git a/src/gtkutil.c b/src/gtkutil.c
index c47386dae00..8eab6ee723d 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -6090,11 +6090,12 @@ xg_im_context_preedit_changed (GtkIMContext *imc, gpointer user_data)
   inev.kind = PREEDIT_TEXT_EVENT;
   inev.arg = build_string_from_utf8 (str);
 
-  Fput_text_property (make_fixnum (min (SCHARS (inev.arg),
-					max (0, cursor))),
-		      make_fixnum (min (SCHARS (inev.arg),
-					max (0, cursor) + 1)),
-		      Qcursor, Qt, inev.arg);
+  if (SCHARS (inev.arg))
+    Fput_text_property (make_fixnum (min (SCHARS (inev.arg) - 1,
+					  max (0, cursor))),
+			make_fixnum (min (SCHARS (inev.arg),
+					  max (0, cursor) + 1)),
+			Qcursor, Qt, inev.arg);
 
   kbd_buffer_store_event (&inev);
 
diff --git a/src/xfns.c b/src/xfns.c
index 7540816416d..9cf6f528198 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -2973,11 +2973,12 @@ xic_preedit_caret_callback (XIC xic, XPointer client_data,
 	  ie.arg = make_string_from_utf8 (output->preedit_chars,
 					  output->preedit_size);
 
-	  Fput_text_property (make_fixnum (min (SCHARS (ie.arg),
-						max (0, output->preedit_caret))),
-			      make_fixnum (max (SCHARS (ie.arg),
-						max (0, output->preedit_caret) + 1)),
-			      Qcursor, Qt, ie.arg);
+	  if (SCHARS (ie.arg))
+	    Fput_text_property (make_fixnum (min (SCHARS (ie.arg) - 1,
+						  max (0, output->preedit_caret))),
+				make_fixnum (max (SCHARS (ie.arg),
+						  max (0, output->preedit_caret) + 1)),
+				Qcursor, Qt, ie.arg);
 
 	  XSETINT (ie.x, 0);
 	  XSETINT (ie.y, 0);
@@ -3196,11 +3197,12 @@ xic_preedit_draw_callback (XIC xic, XPointer client_data,
       ie.arg = make_string_from_utf8 (output->preedit_chars,
 				      output->preedit_size);
 
-      Fput_text_property (make_fixnum (min (SCHARS (ie.arg),
-					    max (0, output->preedit_caret))),
-			  make_fixnum (min (SCHARS (ie.arg),
-					    max (0, output->preedit_caret) + 1)),
-			  Qcursor, Qt, ie.arg);
+      if (SCHARS (ie.arg))
+	Fput_text_property (make_fixnum (min (SCHARS (ie.arg) - 1,
+					      max (0, output->preedit_caret))),
+			    make_fixnum (min (SCHARS (ie.arg),
+					      max (0, output->preedit_caret) + 1)),
+			    Qcursor, Qt, ie.arg);
 
       XSETINT (ie.x, 0);
       XSETINT (ie.y, 0);