muon-discover can't find any packages on first boot until `apt-get update' is done

[rww]

On my first boot after installing Kubuntu vivid, I attempted to use Muon Discover to install some packages. No matter what I searched for, it did not find anything. I could not find a way to manually update the package lists through Muon (this is probably a bug all on its own), and ended up doing `sudo apt-get update' in the terminal. After doing so, Muon found packages just fine.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: muon-discover 4:5.2.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.18.0-13.14-generic 3.18.5
Uname: Linux 3.18.0-13-generic x86_64
ApportVersion: 2.16.1-0ubuntu2
Architecture: amd64
CurrentDesktop: KDE
Date: Sun Feb 15 18:36:05 2015
InstallationDate: Installed on 2015-02-16 (0 days ago)
InstallationMedia: Kubuntu 15.04 "Vivid Vervet" - Alpha amd64 (20150215)
SourcePackage: muon
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daxxi (ubuntuforums-6)]

I'm having great difficulty with the idiot-proof muon - I used to revert to Apper but now it's gone.

Searching for "build-essential" or just "essential", "qtcreator" or just "creator" (in case I missed a hyphen) yields blankness.

If I hunt through all the categories trying to guess which one they're buried in, I find Qt Creator in IDEs OK.

For build-essential and most other, I go back to idiot-friendly apt-get.

Whatever I'm looking for might be there disguised under a friendly name like GCC in font-size 48 with a comment line underneath in the faintest grey possible using italic font size 2 ?