Alt-F10 locks up Unity

Bug Description

Pressing Alt-F10 in any application shows the application's menu in the top panel and then locks up Unity in the sense that all mouse interaction stops working in the application and in the top menu bar, apart from the window close button.

Steps to reproduce:
1. Open an application (e.g. Firefox)
2. Press Alt-F10
-> note: sometimes, you have to keep alt pressed, and tapping F10 multiple times to trigger the bug
3. The application's menu appears in the top panel and stays there
4. Mouse clicks have no effect anymore, whether in the application or in the top menu

Expected behaviour: Alt-F10 shouldn't do anything and certainly not lock the mouse.

Note that this may be related to bug #948519

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.4.0+bzr2054ubuntu0+654 [origin: LP-PPA-unity-team]
ProcVersionSignature: Ubuntu 3.2.0-18.28-generic 3.2.9
Uname: Linux 3.2.0-18-generic x86_64
ApportVersion: 1.94-0ubuntu2
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,move,vpswitch,snap,imgpng,gnomecompat,mousepoll,place,resize,grid,regex,session,wall,animation,workarounds,expo,fade,ezoom,scale,unityshell]
CrashDB: unity
Date: Tue Mar 6 22:41:42 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110901)
ProcEnviron:
LANGUAGE=en_GB:en
TERM=xterm
LANG=en_GB.UTF-8
SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: Upgraded to precise on 2012年02月11日 (24 days ago)

I don't have this issue with the same Unity version from the same PPA.

Which graphic card/driver do you have? That might explain part of the issue.

I have experienced the same problem. I can reproduce it all the time in the following way:

1. Focus any application
2. Press and hold alt
3. Tap F10 a few times
4. Release alt

After this, unity is broken and unusable - the only way to get it back is restarting compiz. It seems rather critical. Currently I'm using unity 5.4.0+bzr2064ubuntu0+654 with compiz 1:0.9.7.0+bzr3035-0ubuntu1~ppa3. My system is an i386 with the fglrx graphics driver.

+1 on both i386 and amd64 machines using unity-team/ppa today.

3v1n0, your fix for this bug is missing the safety check to avoid crashing on Alt+Enter. Like we did for:
https://code.launchpad.net/~vanvugt/unity/fix-960957/+merge/98593

I wonder if that's going to be a problem?...

This bug was fixed in the package unity - 5.8.0-0ubuntu1

---------------
unity (5.8.0-0ubuntu1) precise-proposed; urgency=low

* New upstream release.
- New "push mouse offscreen" feature really difficult to get (LP: #923749)
- unity-2d-panel crashed with SIGSEGV in
unity::indicator::DBusIndicators::Impl::RequestSyncAll() (LP: #864737)
- Pressing "Alt+Enter" causes compiz to crash in CompOption::value() from
unity::UnityScreen::showLauncherKeyTerminate (LP: #960957)
- SEGSIGV after unplugging external monitor (LP: #962693)
- Background colorization should use a different heuristic (LP: #865239)
- compiz+unity3d generates > 50 wakeups a second on idle system
(LP: #917210)
- [FFe, UIFe] HUD - The HUD does not respect launcher autohide or icon
size settings (LP: #921506)
- clicking on folders in the file lens does not open nautilus
(LP: #921665)
- No text inside multirange filters (LP: #927710)
- can't alt-tab restore minimized uis which have an instance on another
workspace (LP: #933397)
- Ubuntu Software Center Unity launcher integration is not working
(LP: #932280)
- The line separator between the launcher and the dash is cleared when
selecting a category (LP: #941082)
- unity-panel-service crashed with SIGSEGV in g_hash_table_foreach()
(LP: #937119)
- Alt-F10 locks up Unity (LP: #948522)
- multimonitor, launcher: Provide an option to display either a single
launcher or a launcher on each display in a multi-monitor environment
(LP: #950136)
- multimonitor: Please give me a way to turn off sticky monitor edges
(LP: #946104)
- Unity 5.6: key bindings (such as Super) don't work on empty workspace or
on slow/loaded systems (LP: #953089)
- Alt+arrows keyboard shortcuts don't invoke Back and Forward navigation
(LP: #953783)
- HUD is sending 2 menu signals instead of 1 (LP: #956878)
- 6th item of HUD not fully visible (LP: #957229)
- HUD: seems to trigger operations more than once (LP: #960503)
- Launcher gets always desaturated when using HUD on secondary monitor
(LP: #961169)
- [5.8 pre staging] launcher is displayed on the left screen, not the
primary one (LP: #961281)
- launcher icons do not re-saturate after dash is closed (LP: #961844)
- Launcher shows arrows for applications on all workspaces (LP: #961977)
- Dash - Implement overlay scrollbars in Dash (LP: #608124)
- [UIFe] Dash - No message displayed when no results are returned in the
Dash (LP: #711199)
- Dash - "See more..." line should be base-aligned with section header
(LP: #748101)
- Dash - Missing category separator line in dash (LP: #850984)
- Dash and Launcher - As soon as a user starts dragging a file from the
Dash, there is a 'flicker' before the Launcher icons that are valid drop
receptacles re-saturate (LP: #863230)
- Dash - When multiple results have equal string match relevancy ranking,
those with equal ranking should be then sorted by frequency of use.
(LP: #871900)
- Keyboard shortcut - F10 shortcut is used to show m...

I don't see this fixed for current Unity

$ unity --version
unity 5.12.0

Yuriy, if you still have problems in Unity 5.12, please log a new bug.