[evolution] Mail: Let the Enter key press in folder tree focus the message list

[Milan Crha <mcrha src gnome org>]

commit 4a9c8ad1e7d68703480b1f0a00ddaaef5f7a4672
Author: Milan Crha <mcrha redhat com>
Date:   Tue Jul 13 12:16:30 2021 +0200

    Mail: Let the Enter key press in folder tree focus the message list
    
    Add an easier way to switch focus from the folder tree to the message
    list by pressing the Enter key.

 src/modules/mail/e-mail-shell-sidebar.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
---
diff --git a/src/modules/mail/e-mail-shell-sidebar.c b/src/modules/mail/e-mail-shell-sidebar.c
index 4eec8500e6..3b1382abfd 100644
--- a/src/modules/mail/e-mail-shell-sidebar.c
+++ b/src/modules/mail/e-mail-shell-sidebar.c
@@ -20,9 +20,11 @@
 
 #include "evolution-config.h"
 
+#include "e-mail-shell-content.h"
 #include "e-mail-shell-sidebar.h"
 
 #include "mail/e-mail-backend.h"
+#include "mail/e-mail-reader.h"
 #include "mail/e-mail-sidebar.h"
 #include "mail/em-folder-utils.h"
 
@@ -125,6 +127,34 @@ mail_shell_sidebar_model_row_changed_cb (GtkTreeModel *model,
                mail_shell_sidebar_selection_changed_cb (E_SHELL_SIDEBAR (mail_shell_sidebar), selection);
 }
 
+static gboolean
+mail_shell_sidebar_tree_view_key_press_cb (GtkWidget *widget,
+                                          GdkEventKey *key_event,
+                                          gpointer user_data)
+{
+       EMailShellSidebar *mail_shell_sidebar = user_data;
+
+       g_return_val_if_fail (E_IS_MAIL_SHELL_SIDEBAR (mail_shell_sidebar), FALSE);
+
+       if ((key_event->state & (GDK_SHIFT_MASK | GDK_CONTROL_MASK | GDK_MOD1_MASK)) == 0 &&
+           (key_event->keyval == GDK_KEY_Return || key_event->keyval == GDK_KEY_KP_Enter) &&
+           gtk_widget_has_focus (widget)) {
+               EShellView *shell_view;
+               EShellContent *shell_content;
+               EMailView *mail_view;
+               GtkWidget *message_list;
+
+               shell_view = e_shell_sidebar_get_shell_view (E_SHELL_SIDEBAR (mail_shell_sidebar));
+               shell_content = e_shell_view_get_shell_content (shell_view);
+               mail_view = e_mail_shell_content_get_mail_view (E_MAIL_SHELL_CONTENT (shell_content));
+               message_list = e_mail_reader_get_message_list (E_MAIL_READER (mail_view));
+
+               gtk_widget_grab_focus (message_list);
+       }
+
+       return FALSE;
+}
+
 static void
 mail_shell_sidebar_get_property (GObject *object,
                                  guint property_id,
@@ -243,6 +273,9 @@ mail_shell_sidebar_constructed (GObject *object)
 
        g_signal_connect (gtk_tree_view_get_model (tree_view), "row-changed",
                G_CALLBACK (mail_shell_sidebar_model_row_changed_cb), shell_sidebar);
+
+       g_signal_connect (tree_view, "key-press-event",
+               G_CALLBACK (mail_shell_sidebar_tree_view_key_press_cb), shell_sidebar);
 }
 
 static gint