diff --git a/src/beval.c b/src/beval.c
index 6b10a65..b7d9226 100644
--- a/src/beval.c
+++ b/src/beval.c
@@ -282,7 +282,7 @@
 	    curbuf = save_curbuf;
 	    if (use_sandbox)
 		++sandbox;
-	    ++textlock;
+	    ++textwinlock;
 
 	    vim_free(result);
 	    result = eval_to_string(bexpr, NULL, TRUE);
@@ -299,7 +299,7 @@
 
 	    if (use_sandbox)
 		--sandbox;
-	    --textlock;
+	    --textwinlock;
 
 	    set_vim_var_string(VV_BEVAL_TEXT, NULL, -1);
 	    if (result != NULL && result[0] != NUL)
diff --git a/src/change.c b/src/change.c
index cfba90b..45d6704 100644
--- a/src/change.c
+++ b/src/change.c
@@ -382,7 +382,7 @@
 
     argv[4].v_type = VAR_LIST;
     argv[4].vval.v_list = buf->b_recorded_changes;
-    ++textlock;
+    ++textwinlock;
 
     for (lnr = buf->b_listener; lnr != NULL; lnr = lnr->lr_next)
     {
@@ -390,7 +390,7 @@
 	clear_tv(&rettv);
     }
 
-    --textlock;
+    --textwinlock;
     list_unref(buf->b_recorded_changes);
     buf->b_recorded_changes = NULL;
 
diff --git a/src/edit.c b/src/edit.c
index 7f4f765..0ac63ec 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -176,9 +176,10 @@
     // Don't allow changes in the buffer while editing the cmdline.  The
     // caller of getcmdline() may get confused.
     // Don't allow recursive insert mode when busy with completion.
-    if (textlock != 0 || ins_compl_active() || compl_busy || pum_visible())
+    if (textwinlock != 0 || textlock != 0
+			  || ins_compl_active() || compl_busy || pum_visible())
     {
-	emsg(_(e_textlock));
+	emsg(_(e_textwinlock));
 	return FALSE;
     }
     ins_compl_clear();	    // clear stuff for CTRL-X mode
@@ -5944,7 +5945,7 @@
     }
 
     // Lock the text to avoid weird things from happening.
-    ++textlock;
+    ++textwinlock;
     set_vim_var_string(VV_CHAR, buf, -1);  // set v:char
 
     res = NULL;
@@ -5958,7 +5959,7 @@
     }
 
     set_vim_var_string(VV_CHAR, NULL, -1);  // clear v:char
-    --textlock;
+    --textwinlock;
 
     // Restore the State, it may have been changed.
     State = save_State;
diff --git a/src/eval.c b/src/eval.c
index 4bd45e9..31dde2f 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -393,7 +393,7 @@
 
 /*
  * Call eval_to_string() without using current local variables and using
- * textlock.  When "use_sandbox" is TRUE use the sandbox.
+ * textwinlock.  When "use_sandbox" is TRUE use the sandbox.
  */
     char_u *
 eval_to_string_safe(
@@ -407,11 +407,11 @@
     save_funccal(&funccal_entry);
     if (use_sandbox)
 	++sandbox;
-    ++textlock;
+    ++textwinlock;
     retval = eval_to_string(arg, nextcmd, FALSE);
     if (use_sandbox)
 	--sandbox;
-    --textlock;
+    --textwinlock;
     restore_funccal();
     return retval;
 }
@@ -576,7 +576,7 @@
     ++emsg_off;
     if (use_sandbox)
 	++sandbox;
-    ++textlock;
+    ++textwinlock;
     *cp = NUL;
     if (eval0(arg, &tv, NULL, TRUE) == FAIL)
 	retval = 0;
@@ -601,7 +601,7 @@
     --emsg_off;
     if (use_sandbox)
 	--sandbox;
-    --textlock;
+    --textwinlock;
 
     return (int)retval;
 }
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index ca69c29..65ef936 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -5749,7 +5749,7 @@
 handle_any_postponed_drop(void)
 {
     if (!drop_busy && drop_filev != NULL
-		     && !text_locked() && !curbuf_locked() && !updating_screen)
+	     && !text_locked() && !curbuf_locked() && !updating_screen)
 	handle_drop_internal();
 }
 #endif
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 6376a5f..48d40cf 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -1318,12 +1318,12 @@
 		c = get_expr_register();
 		if (c == '=')
 		{
-		    // Need to save and restore ccline.  And set "textlock"
+		    // Need to save and restore ccline.  And set "textwinlock"
 		    // to avoid nasty things like going to another buffer when
 		    // evaluating an expression.
-		    ++textlock;
+		    ++textwinlock;
 		    p = get_expr_line();
-		    --textlock;
+		    --textwinlock;
 
 		    if (p != NULL)
 		    {
@@ -2548,17 +2548,17 @@
 
 /*
  * Return TRUE when the text must not be changed and we can't switch to
- * another window or buffer.  Used when editing the command line, evaluating
+ * another window or buffer.  TRUE when editing the command line, evaluating
  * 'balloonexpr', etc.
  */
     int
-text_locked(void)
+text_and_win_locked(void)
 {
 #ifdef FEAT_CMDWIN
     if (cmdwin_type != 0)
 	return TRUE;
 #endif
-    return textlock != 0;
+    return textwinlock != 0;
 }
 
 /*
@@ -2578,10 +2578,22 @@
     if (cmdwin_type != 0)
 	return e_cmdwin;
 #endif
+    if (textwinlock != 0)
+	return e_textwinlock;
     return e_textlock;
 }
 
 /*
+ * Return TRUE when the text must not be changed and/or we cannot switch to
+ * another window.  TRUE while evaluating 'completefunc'.
+ */
+    int
+text_locked(void)
+{
+    return text_and_win_locked() || textlock != 0;
+}
+
+/*
  * Check if "curbuf_lock" or "allbuf_lock" is set and return TRUE when it is
  * and give an error message.
  */
@@ -3560,11 +3572,11 @@
     regname = may_get_selection(regname);
 #endif
 
-    // Need to  set "textlock" to avoid nasty things like going to another
+    // Need to  set "textwinlock" to avoid nasty things like going to another
     // buffer when evaluating an expression.
-    ++textlock;
+    ++textwinlock;
     i = get_spec_reg(regname, &arg, &allocated, TRUE);
-    --textlock;
+    --textwinlock;
 
     if (i)
     {
diff --git a/src/globals.h b/src/globals.h
index 2dceab5..9180bef 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -798,9 +798,15 @@
 				// allowed, e.g. when sourcing .exrc or .vimrc
 				// in current directory
 
-EXTERN int	textlock INIT(= 0);
+EXTERN int	textwinlock INIT(= 0);
 				// non-zero when changing text and jumping to
-				// another window or buffer is not allowed
+				// another window or editing another buffer is
+				// not allowed
+
+EXTERN int	textlock INIT(= 0);
+				// non-zero when changing text is not allowed,
+				// jumping to another window is allowed,
+				// editing another buffer is not allowed.
 
 EXTERN int	curbuf_lock INIT(= 0);
 				// non-zero when the current buffer can't be
@@ -1681,7 +1687,8 @@
 EXTERN char e_sandbox[]		INIT(= N_("E48: Not allowed in sandbox"));
 #endif
 EXTERN char e_secure[]		INIT(= N_("E523: Not allowed here"));
-EXTERN char e_textlock[]	INIT(= N_("E565: Not allowed to change text here"));
+EXTERN char e_textlock[]	INIT(= N_("E578: Not allowed to change text here"));
+EXTERN char e_textwinlock[]	INIT(= N_("E565: Not allowed to change text or change window"));
 #if defined(AMIGA) || defined(MACOS_X) || defined(MSWIN)  \
 	|| defined(UNIX) || defined(VMS)
 EXTERN char e_screenmode[]	INIT(= N_("E359: Screen mode setting not supported"));
diff --git a/src/indent.c b/src/indent.c
index 10c82d8..a1d4d36 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -1760,7 +1760,7 @@
     set_vim_var_nr(VV_LNUM, curwin->w_cursor.lnum);
     if (use_sandbox)
 	++sandbox;
-    ++textlock;
+    ++textwinlock;
 
     // Need to make a copy, the 'indentexpr' option could be changed while
     // evaluating it.
@@ -1773,7 +1773,7 @@
 
     if (use_sandbox)
 	--sandbox;
-    --textlock;
+    --textwinlock;
 
     // Restore the cursor position so that 'indentexpr' doesn't need to.
     // Pretend to be in Insert mode, allow cursor past end of line for "o"
diff --git a/src/insexpand.c b/src/insexpand.c
index 48ab260..bd809b0 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -989,9 +989,9 @@
     dict_set_items_ro(v_event);
 
     recursive = TRUE;
-    textlock++;
+    textwinlock++;
     apply_autocmds(EVENT_COMPLETECHANGED, NULL, NULL, FALSE, curbuf);
-    textlock--;
+    textwinlock--;
     recursive = FALSE;
 
     dict_free_contents(v_event);
@@ -2217,7 +2217,8 @@
     pos = curwin->w_cursor;
     curwin_save = curwin;
     curbuf_save = curbuf;
-    // Lock the text to avoid weird things from happening.
+    // Lock the text to avoid weird things from happening.  Do allow switching
+    // to another window temporarily.
     ++textlock;
 
     // Call a function, which returns a list or dict.
@@ -2442,8 +2443,8 @@
 	return;
     }
 
-    // "textlock" is set when evaluating 'completefunc' but we can change text
-    // here.
+    // "textlock" is set when evaluating 'completefunc' but we can change
+    // text here.
     textlock = 0;
 
     // Check for undo allowed here, because if something was already inserted
diff --git a/src/map.c b/src/map.c
index 85c46a5..2e20d40 100644
--- a/src/map.c
+++ b/src/map.c
@@ -1570,14 +1570,14 @@
 
     // Forbid changing text or using ":normal" to avoid most of the bad side
     // effects.  Also restore the cursor position.
-    ++textlock;
+    ++textwinlock;
     ++ex_normal_lock;
     set_vim_var_char(c);  // set v:char to the typed character
     save_cursor = curwin->w_cursor;
     save_msg_col = msg_col;
     save_msg_row = msg_row;
     p = eval_to_string(expr, NULL, FALSE);
-    --textlock;
+    --textwinlock;
     --ex_normal_lock;
     curwin->w_cursor = save_cursor;
     msg_col = save_msg_col;
diff --git a/src/proto/ex_getln.pro b/src/proto/ex_getln.pro
index a8ca7af..f64bb1f 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, int 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);
+int text_and_win_locked(void);
 void text_locked_msg(void);
 char *get_text_locked_msg(void);
+int text_locked(void);
 int curbuf_locked(void);
 int allbuf_locked(void);
 char_u *getexline(int c, void *cookie, int indent, int do_concat);
diff --git a/src/register.c b/src/register.c
index 2ad136b..e56149f 100644
--- a/src/register.c
+++ b/src/register.c
@@ -932,9 +932,9 @@
     dict_set_items_ro(v_event);
 
     recursive = TRUE;
-    textlock++;
+    textwinlock++;
     apply_autocmds(EVENT_TEXTYANKPOST, NULL, NULL, FALSE, curbuf);
-    textlock--;
+    textwinlock--;
     recursive = FALSE;
 
     // Empty the dictionary, v:event is still valid
diff --git a/src/testdir/test_edit.vim b/src/testdir/test_edit.vim
index a9ba31d..f0bf5cc 100644
--- a/src/testdir/test_edit.vim
+++ b/src/testdir/test_edit.vim
@@ -927,7 +927,7 @@
   set completefunc=CompleteFunc
   call setline(1, ['', 'abcd', ''])
   2d
-  call assert_fails("normal 2G$a\<C-X>\<C-U>", 'E565:')
+  call assert_fails("normal 2G$a\<C-X>\<C-U>", 'E578:')
   bwipe!
 endfunc
 
diff --git a/src/testdir/test_ins_complete.vim b/src/testdir/test_ins_complete.vim
index cec4acf..dbea901 100644
--- a/src/testdir/test_ins_complete.vim
+++ b/src/testdir/test_ins_complete.vim
@@ -491,7 +491,7 @@
   endfunc
   set completefunc=CompleteFunc2
   call setline(1, ['', 'abcd', ''])
-  call assert_fails('exe "normal 2G$a\<C-X>\<C-U>"', 'E565:')
+  call assert_fails('exe "normal 2G$a\<C-X>\<C-U>"', 'E578:')
 
   set completefunc&
   delfunc CompleteFunc
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index 9890377..c7229fc 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -342,7 +342,7 @@
   setlocal completefunc=DummyCompleteOne
   call setline(1, 'one')
   /^one
-  call assert_fails('call feedkeys("A\<C-X>\<C-U>\<C-N>\<Esc>", "x")', 'E565:')
+  call assert_fails('call feedkeys("A\<C-X>\<C-U>\<C-N>\<Esc>", "x")', 'E578:')
   call assert_equal(winid, win_getid())
   call assert_equal('oneDEF', getline(1))
   q!
diff --git a/src/undo.c b/src/undo.c
index c11b048..4bbc0af 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -331,7 +331,7 @@
 
     // Don't allow changes in the buffer while editing the cmdline.  The
     // caller of getcmdline() may get confused.
-    if (textlock != 0)
+    if (textwinlock != 0 || textlock != 0)
     {
 	emsg(_(e_textlock));
 	return FALSE;
diff --git a/src/version.c b/src/version.c
index 6b3a159..8b9fec5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    670,
+/**/
     669,
 /**/
     668,
diff --git a/src/window.c b/src/window.c
index 7c18c06..532d314 100644
--- a/src/window.c
+++ b/src/window.c
@@ -4370,7 +4370,7 @@
 	return;
     }
 #endif
-    if (text_locked())
+    if (text_and_win_locked())
     {
 	beep_flush();
 	text_locked_msg();