[shotwell] Prevent cricial on start-up

[Jens Georg <jensgeorg src gnome org>]

commit d50fc3d02eb804144159ba58fbb218f5b35900c9
Author: Jens Georg <mail jensge org>
Date:   Thu Nov 24 23:02:03 2016 +0100

    Prevent cricial on start-up
    
    Signed-off-by: Jens Georg <mail jensge org>

 src/library/LibraryWindow.vala |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/library/LibraryWindow.vala b/src/library/LibraryWindow.vala
index 4e963bb..9dc737f 100644
--- a/src/library/LibraryWindow.vala
+++ b/src/library/LibraryWindow.vala
@@ -721,6 +721,10 @@ public class LibraryWindow : AppWindow {
     }
 
     private void set_toolbar_visible (bool visible) {
+        if (get_current_page() == null) {
+            return;
+        }
+
         var toolbar = get_current_page ().get_toolbar ();
         if (toolbar != null) {
             toolbar.set_visible (visible);