Unity Dash appears to space its icons according to the text size that is set at the start of the session. But if you go to System Settings / Universal Access / Text Size and set it to Larger, and then bring up Unity Dash again, the icon spacing is unchanged. If however you then log out and log in again, new spacing is used to accommodate the new text size. Conversely if you then reduce the text size to Smallest, Dash will not compensate until you log out and log in again.
ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: unity 4.28.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-15.26-generic 3.0.13
Uname: Linux 3.0.0-15-generic i686
ApportVersion: 1.23-0ubuntu4
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,gnomecompat,grid,imgpng,mousepoll,move,place,regex,resize,session,snap,unitymtgrabhandles,vpswitch,wall,animation,expo,ezoom,fade,scale,unityshell,workarounds]
Date: Tue Jan 31 17:49:09 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
ProcEnviron:
LANGUAGE=en_GB:en
PATH=(custom, no user)
LANG=en_GB.UTF-8
SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
Seems fixed here. Closing.