[devhelp/wip/swilmet/various-code-improvements] sidebar: fix critical message when pressing Ctrl+tab in search entry

[Sébastien Wilmet <swilmet src gnome org>]

commit f46e578565a587ce3665d72c5b19d7261800a2ae
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Fri Oct 9 18:57:38 2015 +0200

    sidebar: fix critical message when pressing Ctrl+tab in search entry
    
    The critical message happened when the search entry is empty:
    
    Gtk-CRITICAL **: gtk_widget_event: assertion 'WIDGET_REALIZED_FOR_EVENT (widget, event)' failed
    
    Which is normal because when the search entry is empty, the hitlist
    isn't shown, the book tree is visible instead.

 src/dh-sidebar.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/dh-sidebar.c b/src/dh-sidebar.c
index ca17909..6b87331 100644
--- a/src/dh-sidebar.c
+++ b/src/dh-sidebar.c
@@ -233,7 +233,8 @@ sidebar_entry_key_press_event_cb (GtkEntry    *entry,
 
         if (event->keyval == GDK_KEY_Tab) {
                 if (event->state & GDK_CONTROL_MASK) {
-                        gtk_widget_grab_focus (GTK_WIDGET (priv->hitlist_view));
+                        if (gtk_widget_is_visible (GTK_WIDGET (priv->hitlist_view)))
+                                gtk_widget_grab_focus (GTK_WIDGET (priv->hitlist_view));
                 } else {
                         gtk_editable_set_position (GTK_EDITABLE (entry), -1);
                         gtk_editable_select_region (GTK_EDITABLE (entry), -1, -1);