compiz team mailing list archive

[matteo sisti sette <1239818@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

This is pretty difficult to reproduce at will, but if you accomplish it
you can see it can be systematically reproduced, and this can easily
happen randomly (that's how I discovered it). When it does, the
consequences could be DISATROUS, so please don't  underestimate the
importance of this bug.

Open two windows of an application. I have been able to reproduce this
in Nautilus, but I think any application with multiple windows will do.
Let's call the two windows WA and WB.

Make sure one of these two windows are focused

Now click on the application's launcher icon. This will produce a compiz
animation transforming the two windows into two reduced non-overlapping
previews, let's call them WAp and WBp ("Window A preview" and "Window B
preview"). If you click on, for instance, WBp, both windows will go back
to their full size and original position, and WB will be focused and
brought to front.

You can repeat this several times.

Now, in order to reproduce the bug, you need to manage to place the two windows WA and WB in such a manner that:
- the area occupied by real window WA virtually overlaps with the area occupied by the preview WBp. Obviously you will never see them overlap, because you either see WA and WB, or WAp and WBp, but you have to place them so that the areas of screen occupied at different times by WA and WBp overlap.
- more specifically, there must be at least one point P in the screen within the area of WBp, which corresponds to a point in WA belonging to a sensitive UI element (e.g. a button) of WA. 
-This point P must not overlap with the area of WB

So now:
- click on the launcher icon so that the two previews WAp and WBp show up
- click on point P

=> Expected result: you are clicking on WBp, so both windows should go
back to their original size and position WA and WB, and WB should
receive focus and brought to front, and NOTHING ELSE SHOULD HAPPEN

=> Observed result: all the described expected result happens, and
besides that, a click at point P within WA is registered, as if WA was
in its original position when you clicked (which it is not), and the
click is processed. If P in the area of WA (which you are NOT seeing
under the cursor when you click) belongs to a button that deletes
something, then that something will be deleted without having ever
clicked on the button.


To sum it up: a click is registered and processed on an area of a window which is NOT what you see under the cursor when you perform the click, so you may perform totally unexpected actions.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: compiz 1:0.9.9~daily13.06.19~13.04-0ubuntu1
ProcVersionSignature: Ubuntu 3.8.0-31.46-generic 3.8.13.8
Uname: Linux 3.8.0-31-generic x86_64
.tmp.unity.support.test.0:
 
ApportVersion: 2.9.2-0ubuntu8.3
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
Date: Mon Oct 14 20:37:19 2013
DistUpgraded: Fresh install
DistroCodename: raring
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] Device [1025:0647]
 NVIDIA Corporation GF117M [GeForce 610M/710M / GT 620M/625M/630M/720M] [10de:1140] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] GeForce 710M [1025:0691]
InstallationDate: Installed on 2013-10-11 (3 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: Acer Aspire V3-571G
MarkForUpload: True
PackageArchitecture: all
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-31-generic root=UUID=5830b30e-69e8-4bb4-8a2b-bc2b43c7414a ro quiet splash vt.handoff=7
SourcePackage: compiz
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/15/2012
dmi.bios.vendor: Acer
dmi.bios.version: V2.07
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: VA50_HC_CR
dmi.board.vendor: Acer
dmi.board.version: Type2 - Board Version
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V2.07
dmi.modalias: dmi:bvnAcer:bvrV2.07:bd10/15/2012:svnAcer:pnAspireV3-571G:pvrV2.07:rvnAcer:rnVA50_HC_CR:rvrType2-BoardVersion:cvnAcer:ct10:cvrV2.07:
dmi.product.name: Aspire V3-571G
dmi.product.version: V2.07
dmi.sys.vendor: Acer
version.compiz: compiz 1:0.9.9~daily13.06.19~13.04-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.43-0ubuntu1.1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.1.4-0ubuntu0.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.1.4-0ubuntu0.1
version.xserver-xorg-core: xserver-xorg-core 2:1.13.3-0ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu2b2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.1.0-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.21.6-0ubuntu4.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.7-0ubuntu1
xserver.bootTime: Mon Oct 14 01:15:32 2013
xserver.configfile: default
xserver.errors:
 
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.13.3-0ubuntu6
xserver.video_driver: intel

** Affects: compiz (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug compiz-0.9 raring ubuntu

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https://bugs.launchpad.net/bugs/1239818

Title:
  Switching between windows may cause you to click on something without
  notice

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