gnome-terminal crashes when you drab tags from one window to another

[Marius Gedminas]

1. Open a gnome-terminal window with two tabs
2. Open a second window, also with two tabs
3. Drag the 2nd tab of the 2nd window onto the rightmost part of the 1st window
4. Drag the 3rd tab of the 1st window back onto the 2nd window

What happens: all terminal windows suddenly close.

journalctl shows

Lap 23 08:42:02 platonas gnome-terminal-[20261]: g_object_ref: assertion 'G_IS_OBJECT (object)' failed
Lap 23 08:42:02 platonas gnome-terminal-[20261]: gtk_container_get_focus_child: assertion 'GTK_IS_CONTAINER (container)' failed
Lap 23 08:42:02 platonas gnome-terminal-server[20261]: **
Lap 23 08:42:02 platonas gnome-terminal-server[20261]: Gtk:ERROR:/build/gtk+3.0-VoKwSM/gtk+3.0-3.20.9/./gtk/gtkwidget.c:5828:gtk_widget_get_frame_clock: assertion failed: (window != NULL)
Lap 23 08:42:02 platonas gnome-terminal-[20261]: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
Lap 23 08:42:02 platonas gnome-terminal-[20261]: gtk_container_get_focus_child: assertion 'GTK_IS_CONTAINER (container)' failed
Lap 23 08:42:05 platonas systemd[5628]: gnome-terminal-server.service: Main process exited, code=dumped, status=6/ABRT
Lap 23 08:42:05 platonas systemd[5628]: gnome-terminal-server.service: Unit entered failed state.
Lap 23 08:42:05 platonas systemd[5628]: gnome-terminal-server.service: Failed with result 'core-dump'.

I've a /var/crash/_usr_lib_gnome-terminal_gnome-terminal-server.1000.crash but no system error dialog presented itself to me yet, so I'm filing this manually.

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: gnome-terminal 3.20.2-1ubuntu5
ProcVersionSignature: Ubuntu 4.8.0-27.29-generic 4.8.1
Uname: Linux 4.8.0-27-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
ApportVersion: 2.20.3-0ubuntu8
Architecture: amd64
CurrentDesktop: GNOME
Date: Wed Nov 23 08:55:33 2016
InstallationDate: Installed on 2016-09-10 (73 days ago)
InstallationMedia: Ubuntu-GNOME 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160720)
SourcePackage: gnome-terminal
UpgradeStatus: Upgraded to yakkety on 2016-10-15 (38 days ago)

[Marius Gedminas (mgedmin)]

This is probably a duplicate of bug 1637333.