overlay scrollbar handle doesn't reveal itself with HiDPI

[Jamie Strandboge]

I have a new Dell XPS 13 9343 with the HiDPI touch screen and am using an external display port monitor. This issue is present with or without the external monitor. While I can see the overlay scrollbars, if I hover the mouse over them, the handle does not pop up so I am unable to grab them and scroll. The only workaround I've found is to disable the overlay scrollbars in /etc/environment:
LIBOVERLAY_SCROLLBAR=0

https://code.launchpad.net/~brandontschaefer/overlay-scrollbar/hidpi-support/+merge/214283 seems like it might be related, but I'm on 15.04 and the overlay scrollbars don't work correctly.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: unity 7.3.2+15.04.20150420-0ubuntu1
ProcVersionSignature: Ubuntu 3.19.0-21.21-generic 3.19.8
Uname: Linux 3.19.0-21-generic x86_64
NonfreeKernelModules: wl
.tmp.unity.support.test.0:

ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Mon Jun 22 11:42:12 2015
DistUpgraded: Fresh install
DistroCodename: vivid
DistroVariant: ubuntu
DkmsStatus:
 bcmwl, 6.30.223.248+bdcom, 3.19.0-18-generic, x86_64: installed
 bcmwl, 6.30.223.248+bdcom, 3.19.0-20-generic, x86_64: installed
 bcmwl, 6.30.223.248+bdcom, 3.19.0-21-generic, x86_64: installed
GraphicsCard:
 Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:0665]
InstallationDate: Installed on 2015-06-13 (8 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MachineType: Dell Inc. XPS 13 9343
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-21-generic root=UUID=7bc4dcd2-0bd8-4e42-b8b7-9f1ed6b8a3e9 ro libata.force=noncq quiet splash vt.handoff=7
SourcePackage: unity
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/25/2015
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A03
dmi.board.name: 0310JH
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA03:bd03/25/2015:svnDellInc.:pnXPS139343:pvr01:rvnDellInc.:rn0310JH:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.name: XPS 13 9343
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.12.1+15.04.20150410.1-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.60-2
version.libgl1-mesa-dri: libgl1-mesa-dri 10.5.2-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.5.2-0ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.17.1-0ubuntu3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.0-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.5.0-1ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917-1~exp1ubuntu2.2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu2build1
xserver.bootTime: Mon Jun 22 10:53:54 2015
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 5153
 vendor SHP
xserver.version: 2:1.17.1-0ubuntu3

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Cris Dywan (kalikiana)]

This is not specific to the XPS 13. On my T300 Chi I'm seeing the same.

[Jamie Strandboge (jdstrand)]

This is resolved in wily. I removed LIBOVERLAY_SCROLLBAR=0 from /etc/environment and then logged in. If I open a terminal or evince, the overlay is not too small, I move the cursor over it, it expands inward and is easy to grab.