[geary: 1/2] composer: Fix close buttons

[Michael Gratton <mjog src gnome org>]

commit 2cf590a0620160647cfbf8408dbfc108bbbdf55c
Author: James Westman <flyingpimonster gmail com>
Date:   Wed Jan 29 15:10:28 2020 -0600

    composer: Fix close buttons
    
    7d207dbb broke the close buttons in the composer headerbar again. This
    makes sure the close button only appears in the composer headerbar if it
    is part of the main window's headerbar.
    
    Fixes #685.

 src/client/composer/composer-headerbar.vala | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/client/composer/composer-headerbar.vala b/src/client/composer/composer-headerbar.vala
index fd2680a5..33cb3652 100644
--- a/src/client/composer/composer-headerbar.vala
+++ b/src/client/composer/composer-headerbar.vala
@@ -38,7 +38,6 @@ public class Composer.Headerbar : Gtk.HeaderBar {
         Gtk.Settings.get_default().notify["gtk-decoration-layout"].connect(
             on_gtk_decoration_layout_changed
         );
-        this.show_close_button = this.config.desktop_environment != UNITY;
     }
 
     public override void destroy() {
@@ -71,6 +70,9 @@ public class Composer.Headerbar : Gtk.HeaderBar {
             this.set_attached(true);
             break;
         }
+
+        this.show_close_button = (mode == Widget.PresentationMode.PANED
+                                  && this.config.desktop_environment != UNITY);
     }
 
     private void set_attached(bool is_attached) {