diff --git a/src/buffer.c b/src/buffer.c
index efec431..e775398 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2407,12 +2407,7 @@
     if (buf == curbuf)
 	return OK;
 
-    if (text_locked())
-    {
-	text_locked_msg();
-	return FAIL;
-    }
-    if (curbuf_locked())
+    if (text_or_buf_locked())
 	return FAIL;
 
     // altfpos may be changed by getfile(), get it now
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 9dadfbf..623bd1d 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -2740,6 +2740,21 @@
 }
 
 /*
+ * Check for text, window or buffer locked.
+ * Give an error message and return TRUE if something is locked.
+ */
+    int
+text_or_buf_locked(void)
+{
+    if (text_locked())
+    {
+	text_locked_msg();
+	return TRUE;
+    }
+    return curbuf_locked();
+}
+
+/*
  * Check if "curbuf_lock" or "allbuf_lock" is set and return TRUE when it is
  * and give an error message.
  */
@@ -4379,6 +4394,10 @@
     int			save_KeyTyped;
 #endif
 
+    // Can't do this when text or buffer is locked.
+    if (text_or_buf_locked())
+	return K_IGNORE;
+
     // Can't do this recursively.  Can't do it when typing a password.
     if (cmdwin_type != 0
 # if defined(FEAT_CRYPT) || defined(FEAT_EVAL)
diff --git a/src/proto/ex_getln.pro b/src/proto/ex_getln.pro
index 8c8bd0e..bcc310c 100644
--- a/src/proto/ex_getln.pro
+++ b/src/proto/ex_getln.pro
@@ -3,9 +3,10 @@
 char_u *getcmdline(int firstc, long count, int indent, getline_opt_T do_concat);
 char_u *getcmdline_prompt(int firstc, char_u *prompt, int attr, int xp_context, char_u *xp_arg);
 int check_opt_wim(void);
+int text_locked(void);
 void text_locked_msg(void);
 char *get_text_locked_msg(void);
-int text_locked(void);
+int text_or_buf_locked(void);
 int curbuf_locked(void);
 int allbuf_locked(void);
 char_u *getexline(int c, void *cookie, int indent, getline_opt_T options);
@@ -32,8 +33,8 @@
 void f_getcmdcompltype(typval_T *argvars, typval_T *rettv);
 void f_getcmdline(typval_T *argvars, typval_T *rettv);
 void f_getcmdpos(typval_T *argvars, typval_T *rettv);
-void f_setcmdpos(typval_T *argvars, typval_T *rettv);
 void f_getcmdscreenpos(typval_T *argvars, typval_T *rettv);
+void f_setcmdpos(typval_T *argvars, typval_T *rettv);
 void f_getcmdtype(typval_T *argvars, typval_T *rettv);
 int get_cmdline_firstc(void);
 int get_list_range(char_u **str, int *num1, int *num2);
diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index c8df09f..3c87faf 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -1035,6 +1035,31 @@
   delfunc Repl
 endfunc
 
+" This was opening a command line window from the expression
+func Test_sub_open_cmdline_win()
+  " the error only happens in a very specific setup, run a new Vim instance to
+  " get a clean starting point.
+  let lines =<< trim [SCRIPT]
+    norm o0000000000000000000000000000000000000000000000000000
+    func Replace()
+      norm q/
+    endfunc
+    s/\%')/\=Replace()
+    redir >Xresult
+    messages
+    redir END
+    qall!
+  [SCRIPT]
+  call writefile(lines, 'Xscript')
+  if RunVim([], [], '-u NONE -S Xscript')
+    let messages = readfile('Xresult')
+    call assert_match('E565: Not allowed to change text or change window', messages[3])
+  endif
+
+  call delete('Xscript')
+  call delete('Xresult')
+endfunc
+
 " Test for the 2-letter and 3-letter :substitute commands
 func Test_substitute_short_cmd()
   new
diff --git a/src/version.c b/src/version.c
index 18a1fdb..a15bb3e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5043,
+/**/
     5042,
 /**/
     5041,
diff --git a/src/window.c b/src/window.c
index f2913d4..9b5ac97 100644
--- a/src/window.c
+++ b/src/window.c
@@ -4585,14 +4585,11 @@
 	return;
     }
 #endif
-    if (text_locked())
+    if (text_or_buf_locked())
     {
 	beep_flush();
-	text_locked_msg();
 	return;
     }
-    if (curbuf_locked())
-	return;
 
     if (wp->w_buffer != curbuf)
 	reset_VIsual_and_resel();