diff --git a/runtime/doc/popup.txt b/runtime/doc/popup.txt
index 5950c47..fdf28a5 100644
--- a/runtime/doc/popup.txt
+++ b/runtime/doc/popup.txt
@@ -150,7 +150,7 @@
 - When the job ends, the popup window closes.
 - The popup window can be closed with `popup_close()`, the terminal buffer
   then becomes hidden.
-- It is not possible to enter Terminal-Normal mode.
+- It is not possible to open a second popup window with a terminal. *E861*
 - The default Pmenu color is only used for the border and padding.  To change
   the color of the terminal itself set the Terminal highlight group before
   creating the terminal.  Setting 'wincolor' later can work but requires the
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 94a3367..5447b74 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -2918,8 +2918,12 @@
 	{
 	    case ADDR_LINES:
 	    case ADDR_OTHER:
-		// default is current line number
-		eap->line2 = curwin->w_cursor.lnum;
+		// Default is the cursor line number.  Avoid using an invalid
+		// line number though.
+		if (curwin->w_cursor.lnum > curbuf->b_ml.ml_line_count)
+		    eap->line2 = curbuf->b_ml.ml_line_count;
+		else
+		    eap->line2 = curwin->w_cursor.lnum;
 		break;
 	    case ADDR_WINDOWS:
 		eap->line2 = CURRENT_WIN_NR;
diff --git a/src/popupwin.c b/src/popupwin.c
index 4ee097a..79021c3 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -1758,6 +1758,25 @@
 }
 
 /*
+ * Return TRUE if there is any popup window with a terminal buffer.
+ */
+    static int
+popup_terminal_exists(void)
+{
+    win_T	*wp;
+    tabpage_T	*tp;
+
+    FOR_ALL_POPUPWINS(wp)
+	if (wp->w_buffer->b_term != NULL)
+	    return TRUE;
+    FOR_ALL_TABPAGES(tp)
+	FOR_ALL_POPUPWINS_IN_TAB(tp, wp)
+	    if (wp->w_buffer->b_term != NULL)
+		return TRUE;
+    return FALSE;
+}
+
+/*
  * popup_create({text}, {options})
  * popup_atcursor({text}, {options})
  * etc.
@@ -1786,6 +1805,13 @@
 		semsg(_(e_nobufnr), argvars[0].vval.v_number);
 		return NULL;
 	    }
+#ifdef FEAT_TERMINAL
+	    if (buf->b_term != NULL && popup_terminal_exists())
+	    {
+		emsg(_("E861: Cannot open a second popup with a terminal"));
+		return NULL;
+	    }
+#endif
 	}
 	else if (!(argvars[0].v_type == VAR_STRING
 			&& argvars[0].vval.v_string != NULL)
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index feaa5e4..8c917bc 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -2426,10 +2426,10 @@
   let g:test_is_flaky = 1
 
   let origwin = win_getid()
-  let ptybuf = term_start(&shell, #{hidden: 1})
-  let winid = popup_create(ptybuf, #{minwidth: 40, minheight: 10})
+  let termbuf = term_start(&shell, #{hidden: 1})
+  let winid = popup_create(termbuf, #{minwidth: 40, minheight: 10})
   " Wait for shell to start
-  call WaitForAssert({-> assert_equal("run", job_status(term_getjob(ptybuf)))})
+  call WaitForAssert({-> assert_equal("run", job_status(term_getjob(termbuf)))})
   sleep 100m
   " Check this doesn't crash
   call assert_equal(winnr(), winnr('j'))
@@ -2440,11 +2440,16 @@
   " Cannot quit while job is running
   call assert_fails('call feedkeys("\<C-W>:quit\<CR>", "xt")', 'E948:')
 
-  " Cannot enter Terminal-Normal mode.
+  " Cannot enter Terminal-Normal mode. (TODO: but it works...)
   call feedkeys("xxx\<C-W>N", 'xt')
   call assert_fails('call feedkeys("gf", "xt")', 'E863:')
   call feedkeys("a\<C-U>", 'xt')
 
+  " Cannot open a second one.
+  let termbuf2 = term_start(&shell, #{hidden: 1})
+  call assert_fails('call popup_create(termbuf2, #{})', 'E861:')
+  call term_sendkeys(termbuf2, "exit\<CR>")
+
   " Exiting shell closes popup window
   call feedkeys("exit\<CR>", 'xt')
   " Wait for shell to exit
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index ab1961a..7f85f6c 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -2587,9 +2587,8 @@
   let buf1 = term_start(&shell, #{hidden: 1})
   let win1 = popup_create(buf1, {})
   let buf2 = term_start(&shell, #{hidden: 1})
-  let win2 = popup_create(buf2, {})
+  call assert_fails('call popup_create(buf2, {})', 'E861:')
   call popup_close(win1)
-  call popup_close(win2)
   exe buf1 .. 'bwipe!'
   exe buf2 .. 'bwipe!'
 endfunc
@@ -2619,10 +2618,8 @@
   CheckExecutable sh
 
   set hidden
-  let g:buf0 = term_start('sh', #{hidden: 1})
+  let g:buf0 = term_start('sh', #{hidden: 1, term_finish: 'close'})
   call popup_create(g:buf0, {})
-  let g:buf1 = term_start('sh', #{hidden: 1, term_finish: 'close'})
-  call popup_create(g:buf1, {})
   call assert_fails("call term_start(['sh', '-c'], #{curwin: 1})", 'E863:')
 
   call popup_clear(1)
diff --git a/src/version.c b/src/version.c
index aa03f90..92f5660 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    791,
+/**/
     790,
 /**/
     789,