[baobab/wip/gtk4: 1/5] fix button

[Stefano Facchini <sfacchini src gnome org>]

commit e3efee729d1711dcafb8e19ba226fb1a33c297e9
Author: Stefano Facchini <stefano facchini gmail com>
Date:   Sun Oct 29 15:37:33 2017 +0100

    fix button

 src/baobab-window.vala |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/src/baobab-window.vala b/src/baobab-window.vala
index 75838d1..f45035a 100644
--- a/src/baobab-window.vala
+++ b/src/baobab-window.vala
@@ -185,8 +185,10 @@ namespace Baobab {
             set_ui_state (home_page, false);
 
             button_press_event.connect ((event) => {
+                uint button;
+                event.get_button(out button);
                 // mouse back button
-                if (event.button == 8) {
+                if (button == 8) {
                     lookup_action ("show-home-page").activate (null);
                     return Gdk.EVENT_STOP;
                 }