[evolution] Bug 594017 - Crash on set preview visible

[Matthew Barnes <mbarnes src gnome org>]

commit 70ed8286d0293691e828ec46291fa1b0a549cc63
Author: Milan Crha <mcrha redhat com>
Date:   Sat Sep 12 23:21:30 2009 -0500

    Bug 594017 - Crash on set preview visible

 modules/mail/e-mail-shell-content.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/modules/mail/e-mail-shell-content.c b/modules/mail/e-mail-shell-content.c
index 10c714a..c1e4c13 100644
--- a/modules/mail/e-mail-shell-content.c
+++ b/modules/mail/e-mail-shell-content.c
@@ -838,10 +838,14 @@ e_mail_shell_content_set_preview_visible (EMailShellContent *mail_shell_content,
 	if (preview_visible) {
 		EMailReader *reader;
 		MessageList *message_list;
+		const gchar *cursor_uid;
 
 		reader = E_MAIL_READER (mail_shell_content);
 		message_list = e_mail_reader_get_message_list (reader);
-		e_mail_reader_set_message (reader, message_list->cursor_uid);
+		cursor_uid = message_list->cursor_uid;
+
+		if (cursor_uid != NULL)
+			e_mail_reader_set_message (reader, cursor_uid);
 	}
 
 	mail_shell_content->priv->preview_visible = preview_visible;