Tweaks windows - attach modal dialogs OFF has no effect

Tweaks - Windows - I set to OFF the option in Attach Modal Dialogs but child windows are still stuck to parent window. Also after restart.
corrado@corrado-HP-p3-aa:~$ inxi -Fxx
System: Host: corrado-HP-p3-aa Kernel: 4.12.0-13-generic x86_64 bits: 64 gcc: 7.2.0
           Desktop: Gnome 3.25.91 (Gtk 3.22.19-0ubuntu1) dm: gdm3
           Distro: Ubuntu Artful Aardvark (development branch)
Machine: Device: laptop System: Hewlett-Packard product: HP 250 G3 Notebook PC v: 0991100000000000000600087 serial: N/A
           Mobo: Hewlett-Packard model: 2211 v: 86.49 serial: N/A UEFI: Insyde v: F.36 date: 12/18/2014
           Chassis: type: 10 serial: N/A
Battery BAT1: charge: 20.1 Wh 86.1% condition: 23.4/23.4 Wh (100%) volts: 12.7/11.1
           model: 13-42 OA03031 serial: 02550 01/07/2015 status: Charging
CPU: Dual core Intel Core i5-4210U (-HT-MCP-) arch: Haswell rev.1 cache: 3072 KB
           flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 9578
           clock speeds: min/max: 800/2700 MHz 1: 799 MHz 2: 799 MHz 3: 1011 MHz 4: 799 MHz
Graphics: Card: Intel Haswell-ULT Integrated Graphics Controller bus-ID: 00:02.0 chip-ID: 8086:0a16
           Display Server: x11 (X.Org 1.19.3 ) driver: i915 Resolution: 1366x768@60.00hz
           OpenGL: renderer: Mesa DRI Intel Haswell Mobile
           version: 4.5 Mesa 17.2.0 (compat-v: 3.0) Direct Render: Yes
Audio: Card-1 Intel 8 Series HD Audio Controller driver: snd_hda_intel bus-ID: 00:1b.0 chip-ID: 8086:9c20
           Card-2 Intel Haswell-ULT HD Audio Controller driver: snd_hda_intel bus-ID: 00:03.0 chip-ID: 8086:0a0c
           Sound: Advanced Linux Sound Architecture v: k4.12.0-13-generic
Network: Card-1: Realtek RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller
           driver: r8169 v: 2.3LK-NAPI port: 3000 bus-ID: 08:00.0 chip-ID: 10ec:8136
           IF: enp8s0 state: down mac: 5c:b9:01:06:ba:ce
           Card-2: Ralink RT3290 Wireless 802.11n 1T/1R PCIe
           driver: rt2800pci v: 2.3.0 bus-ID: 09:00.0 chip-ID: 1814:3290
           IF: wlo1 state: up mac: ac:d1:b8:82:03:5d
Drives: HDD Total Size: 500.1GB (2.0% used)
           ID-1: /dev/sda model: ST500LT012 size: 500.1GB serial: W3PEAWM4
Partition: ID-1: / size: 32G used: 5.3G (18%) fs: ext4 dev: /dev/sda3
           ID-2: swap-1 size: 4.29GB used: 0.00GB (0%) fs: swap dev: /dev/sda2
RAID: System: supported: N/A
           No RAID devices: /proc/mdstat, md_mod kernel module present
           Unused Devices: none
Sensors: System Temperatures: cpu: 45.0C mobo: 45.0C
           Fan Speeds (in rpm): cpu: N/A
Info: Processes: 238 Uptime: 26 min Memory: 1282.5/3880.1MB Init: systemd v: 234 runlevel: 5 Gcc sys: N/A
           Client: Shell (bash 4.4.121 running in gnome-terminal-) inxi: 2.3.37
corrado@corrado-HP-p3-aa:~$

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: gnome-tweak-tool 3.26.0-0ubuntu2
ProcVersionSignature: Ubuntu 4.12.0-13.14-generic 4.12.10
Uname: Linux 4.12.0-13-generic x86_64
ApportVersion: 2.20.7-0ubuntu1
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Sep 15 16:22:38 2017
ExecutablePath: /usr/bin/gnome-tweak-tool
InstallationDate: Installed on 2017-09-12 (3 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170911)
InterpreterPath: /usr/bin/python3.6
PackageArchitecture: all
Python3Details: /usr/bin/python3.6, Python 3.6.2, python3-minimal, 3.6.1-0ubuntu3
PythonDetails: /usr/bin/python2.7, Python 2.7.14rc1, python-minimal, 2.7.13-2
SourcePackage: gnome-tweak-tool
UpgradeStatus: No upgrade log present (probably fresh install)