Hard to find many packages: unclear where "technical items" are hidden

This is a usability issue.

I tried to install Xen using Ubuntu Software Center. First I searched for "xen" but didn't find the hypervisor. I tried a few options like "*xen*" and some others, but I only got xenwatch, xenlog and vnc-client among my search results. I gave up and used apt-get.

I later discovered:

1. Searching for "xen-" instead of just "xen" DOES show xen-hypervisor options. Explain that!?
2. There's a well hidden "Show XX technical items" at the bottom of the window.

This is bad usability. The "technical items" definition seems useless. Aren't xenwatch, xenlog and vnc-client technical items? What exactly is a "technical item"?

But if you insist on hiding packages like that, there should be a clearly visible meta-entry among the search results to show the rest of the entries.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: software-center 5.4.1.4
ProcVersionSignature: Ubuntu 3.5.0-25.39-generic 3.5.7.4
Uname: Linux 3.5.0-25-generic i686
ApportVersion: 2.6.1-0ubuntu10
Architecture: i386
Date: Mon Mar 4 16:29:15 2013
InstallationDate: Installed on 2010-10-25 (861 days ago)
InstallationMedia: Ubuntu 10.04.1 LTS "Lucid Lynx" - Release i386 (20100816.1)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 SHELL=/bin/bash
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 XDG_RUNTIME_DIR=<set>
SourcePackage: software-center
UpgradeStatus: Upgraded to quantal on 2012-12-20 (74 days ago)