[balsa/gtk4] balsa-message: Restore a needed gtk_widget_show()

[Peter Bloomfield <peterb src gnome org>]

commit 46596f5fe2cf48f890af6bf73295de3eceab98e3
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Fri Nov 20 10:13:20 2020 -0500

    balsa-message: Restore a needed gtk_widget_show()
    
    We hide the preview when changing its content, so it must be explicitly
    shown again when the new message has been set.

 src/balsa-message.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/balsa-message.c b/src/balsa-message.c
index b13db635f..82574748d 100644
--- a/src/balsa-message.c
+++ b/src/balsa-message.c
@@ -1347,6 +1347,7 @@ balsa_message_set(BalsaMessage * balsa_message, LibBalsaMailbox * mailbox, guint
 
     display_headers(balsa_message);
     display_content(balsa_message);
+    gtk_widget_show(GTK_WIDGET(balsa_message));
 
     if (balsa_message->info_count > 1)
         gtk_widget_show(balsa_message->switcher);