Xfce4-terminal window restore button doesn't work. After maximize the Xfce4-terminal window, clicking restore button doesn't restore original size.

reproduce procedure
1 open Xfce4-terminal
2 click the maximize button to maximize Xfce4-terminal window
3 click the restore button, the Xfce4-terminal window doesn't restore the original size.

[l@HP14 ~]$ uname -a
Linux HP14 4.20.11-200.fc29.x86_64 #1 SMP Wed Feb 20 15:56:08 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
[l@HP14 ~]$ 
[l@HP14 ~]$ xfce4-terminal -V
xfce4-terminal 0.8.7.4 (Xfce 4.12)

Copyright (c) 2003-2018
	The Xfce development team. All rights reserved.

Written by Benedikt Meurer <benny@xfce.org>,
Nick Schermer <nick@xfce.org>
and Igor Zakharov <f2404@yandex.ru>.

Please report bugs to <https://bugzilla.xfce.org/>.