[evolution] Shift+Click on switcher button to open a new window

[Milan Crha <mcrha src gnome org>]

commit cc783f32f7a9c8da027d0368f4a4b929ce9e9b85
Author: Milan Crha <mcrha redhat com>
Date:   Fri May 18 08:47:52 2018 +0200

    Shift+Click on switcher button to open a new window
    
    Both middle-click and Shift+left-click open a new window when
    pressed on the switcher button. The Shift+left-click had been
    added for consistency with other applications.
    
    Requested downstream at:
    https://bugzilla.redhat.com/show_bug.cgi?id=1308665

 src/shell/e-shell-switcher.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/src/shell/e-shell-switcher.c b/src/shell/e-shell-switcher.c
index db1e63a..9f0c8eb 100644
--- a/src/shell/e-shell-switcher.c
+++ b/src/shell/e-shell-switcher.c
@@ -617,13 +617,17 @@ tool_item_button_cb (GtkWidget *internal_widget,
                      GdkEvent *button_event,
                      GtkAction *action)
 {
+       guint32 my_mods = GDK_SHIFT_MASK | GDK_CONTROL_MASK | GDK_MOD1_MASK |
+               GDK_SUPER_MASK | GDK_HYPER_MASK | GDK_META_MASK;
+       GdkModifierType event_state = 0;
        guint event_button = 0;
 
        g_return_val_if_fail (GTK_IS_ACTION (action), FALSE);
 
        gdk_event_get_button (button_event, &event_button);
+       gdk_event_get_state (button_event, &event_state);
 
-       if (event_button == 2) {
+       if (event_button == 2 || (event_button == 1 && (event_state & my_mods) == GDK_SHIFT_MASK)) {
                gtk_action_activate (action);
                return TRUE;
        }