Dash sometimes takes a long time (2-3 seconds) to appear

[Alan Pope 🍺🐧🐱 🦄]

Sometimes on my 12.04 system I press <super> and am surprised that the dash doesn't appear. I sometimes think I didn't hit it right so press a couple more times. Then a couple of seconds later the dash flickers on and off, seemingly catching up with my keypresses.

More recently I've taken to pressing super and waiting to see how long it takes to appear. It can sometimes take as long as 3 seconds before I see any activity. My machine is an i7 X220 with external 1080p screen. It doesn't happen every time, but often enough to be annoying.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.16.0+bzr2408sruubuntu0+709 [origin: LP-PPA-unity-team-sru]
ProcVersionSignature: Ubuntu 3.2.0-32.51-generic 3.2.30
Uname: Linux 3.2.0-32-generic x86_64
ApportVersion: 2.0.1-0ubuntu14
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]
CrashDB: unity
Date: Mon Oct 15 11:59:08 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)