synaptic won't start from unity dash

since about a week or two I can't start synaptic from unity dash. it runs great, when launching it out from command line, but somehow fails when using a unity dash launcher - dash disappears normally, but it doesn't start synaptic.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: synaptic 0.80.2
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Mon Nov 25 22:41:52 2013
InstallationDate: Installed on 2012-12-15 (345 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
SourcePackage: synaptic
UpgradeStatus: Upgraded to saucy on 2013-10-24 (32 days ago)