[longomatch] Handle changes in fileset on initial show.

[Andoni Morales Alastruey <amorales src gnome org>]

commit 787e7ab821811d79a2a9d4ad570c4cfb83660388
Author: Julien Moutte <julien fluendo com>
Date:   Sat Mar 14 09:42:24 2015 +0100

    Handle changes in fileset on initial show.
    
    The number of files could change triggering mode change in the synchronisation mode.

 LongoMatch.GUI/Gui/Component/ProjectPeriods.cs |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/LongoMatch.GUI/Gui/Component/ProjectPeriods.cs b/LongoMatch.GUI/Gui/Component/ProjectPeriods.cs
index 3e099c6..bcccfe6 100644
--- a/LongoMatch.GUI/Gui/Component/ProjectPeriods.cs
+++ b/LongoMatch.GUI/Gui/Component/ProjectPeriods.cs
@@ -222,6 +222,15 @@ namespace LongoMatch.Gui.Component
                                main_cam_label.Text = fileSet.First ().Name;
                                main_cam_playerbin.ShowControls = false;
                                main_cam_playerbin.Open (fileSet);
+
+                               if (fileSet.Count > 1) {
+                                       // Start with initial didactic message
+                                       ShowDidactic (DidacticMessage.Initial);
+                               } else {
+                                       // Just in case it was previously visible, a mediafile might still be 
loaded if 
+                                       // the user is going back and forth adding/removing files to the set.
+                                       HideSecondaryPlayer ();
+                               }
                        }
                }