切换窗口时为啥出现了两层窗口栏

[Gaarahan]

我的Ｕｂｕｎｔｕ在使用alt+tab切换窗口时为什么出现了两层窗口栏，美化方面只按照网上教程安装了unity-tweak-tool ,然后安装了numix主题.
切换时有时会搞混，求告知怎么关闭

[poloshiao]

1. 把下面指令 複製 貼進終端機 執行
1-1. sudo cat /etc/os-release
1-2. sudo lshw -numeric -class video
1-3. echo $DESKTOP_SESSION
1-4. xrandr -q
1-5. xrandr --verbose | grep -A8 EDID
把結果直接複製貼上來

[Gaarahan]

1. 把下面指令 複製 貼進終端機 執行
1-1. sudo cat /etc/os-release
1-2. sudo lshw -numeric -class video
1-3. echo $DESKTOP_SESSION
1-4. xrandr -q
1-5. xrandr --verbose | grep -A8 EDID
把結果直接複製貼上來

１．
NAME="Ubuntu"
VERSION="16.04.4 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.4 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial
２．*-display
description: VGA compatible controller
product: Carrizo [1002:9874]
vendor: Advanced Micro Devices, Inc. [AMD/ATI] [1002]
physical id: 1
bus info: pci@0000:00:01.0
version: ca
width: 64 bits
clock: 33MHz
capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
configuration: driver=amdgpu latency=0
resources: irq:40 memory:e0000000-efffffff memory:f0000000-f07fffff ioport:4000(size=256) memory:f0d00000-f0d3ffff memory:c0000-dffff
３．ubuntu
4.Screen 0: minimum 320 x 200, current 1366 x 768, maximum 16384 x 16384
eDP connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
1366x768 60.02*+
1280x720 59.97
1152x768 59.95
1024x768 59.95
800x600 59.96
848x480 59.94
720x480 59.94
640x480 59.94
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
5.EDID:
00ffffffffffff0006afec7000000000
18190104952213780250259358579229
22505400000001010101010101010101
010101010101ce1d56c050003030080a
310058c1100000180000000f00000000
00000000000000000020000000fe0041
554f0a202020202020202020000000fe
004231353658544e30372e30200a00fd