[chronojump] If no session, label_session will show ----

[Xavier de Blas <xaviblas src gnome org>]

commit 4e7f7b68800a95b66f331b6a9f4f0c636abfe7db
Author: Xavier de Blas <xaviblas gmail com>
Date:   Wed Jul 28 13:32:13 2021 +0200

    If no session, label_session will show ----

 src/gui/app1/chronojump.cs | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/gui/app1/chronojump.cs b/src/gui/app1/chronojump.cs
index 57702e6fd..3e837aa66 100644
--- a/src/gui/app1/chronojump.cs
+++ b/src/gui/app1/chronojump.cs
@@ -2673,6 +2673,9 @@ public partial class ChronoJumpWindow
                        title += " - " + sessionName;
                        label_current_session.Text = sessionName;
                        label_current_session.TooltipText = sessionName;
+               } else {
+                       label_current_session.Text = "----";
+                       label_current_session.TooltipText = "----";
                }
 
                if(mode != Constants.Menuitem_modes.UNDEFINED)