Quicksearch doesn't find packages in PPA. See Launchpad bug 293402.

[MSE]

Failed to find any packages matching "jup", "jupiter", or any string in between.
That's after adding repository ppa:webupd8team/jupiter
And after running apt-get update.

The packages "jupiter" and "jupiter-support-eee" appeared in the alphabetical package list.
And the "Search for packages" button successfully found those two packages, searching for "jupiter".

Looks like I'm the 2nd user to report this issue on Launchpad.
See bug report 293402.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: synaptic 0.75.2ubuntu8
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic i686
ApportVersion: 1.23-0ubuntu3
Architecture: i386
CasperVersion: 1.287
Date: Wed Dec 14 03:24:31 2011
ExecutablePath: /usr/sbin/synaptic
LiveMediaBuild: Xubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
ProcEnviron:
 SHELL=/bin/bash
 LANG=en_US.UTF-8
 PATH=(custom, no user)
SourcePackage: synaptic
UpgradeStatus: No upgrade log present (probably fresh install)

[dino99 (9d9)]

That version is too old and no more maintained