[balsa] mailbox: Check for finalized mailbox

[Peter Bloomfield <peterb src gnome org>]

commit 8e6b6cc2c048975f3c87d777656fa6b121235575
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Fri Jan 10 18:09:48 2020 -0500

    mailbox: Check for finalized mailbox
    
    * libbalsa/mailbox.c (lbm_changed_idle_cb):

 ChangeLog          | 6 ++++++
 libbalsa/mailbox.c | 3 ++-
 2 files changed, 8 insertions(+), 1 deletion(-)
---
diff --git a/ChangeLog b/ChangeLog
index 43b77b77a..b73205500 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2020-01-10  Peter Bloomfield  <pbloomfield bellsouth net>
+
+       mailbox: Check for finalized mailbox
+
+       * libbalsa/mailbox.c (lbm_changed_idle_cb):
+
 2020-01-10  Peter Bloomfield  <pbloomfield bellsouth net>
 
        mailbox-local: Check for error return value
diff --git a/libbalsa/mailbox.c b/libbalsa/mailbox.c
index 0ffacb80c..ed3e0f250 100644
--- a/libbalsa/mailbox.c
+++ b/libbalsa/mailbox.c
@@ -734,7 +734,8 @@ lbm_changed_idle_cb(LibBalsaMailbox * mailbox)
     libbalsa_lock_mailbox(mailbox);
     g_signal_emit(mailbox, libbalsa_mailbox_signals[CHANGED], 0);
     priv->changed_idle_id = 0;
-    libbalsa_unlock_mailbox(mailbox);
+    if (LIBBALSA_IS_MAILBOX(mailbox))
+        libbalsa_unlock_mailbox(mailbox);
 
     return G_SOURCE_REMOVE;
 }