diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7716ff9b1aa..20ceaa26ae7 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2021-01-05  Hannes Domani  <ssbssa@yahoo.de>
+
+	* tui/tui-source.c (tui_source_window::show_line_number):
+	Redraw second space after line number.
+
 2021-01-05  Hannes Domani  <ssbssa@yahoo.de>
 
 	PR tui/26927
diff --git a/gdb/tui/tui-source.c b/gdb/tui/tui-source.c
index 6254e8d7f16..97500495f9d 100644
--- a/gdb/tui/tui-source.c
+++ b/gdb/tui/tui-source.c
@@ -233,6 +233,8 @@ tui_source_window::show_line_number (int offset) const
 {
   int lineno = m_content[0].line_or_addr.u.line_no + offset;
   char text[20];
-  xsnprintf (text, sizeof (text), "%*d ", m_digits - 1, lineno);
+  /* To completely overwrite the previous border when the source window height
+     is increased, both spaces after the line number have to be redrawn.  */
+  xsnprintf (text, sizeof (text), "%*d  ", m_digits - 1, lineno);
   waddstr (handle.get (), text);
 }