Error installing grub dialog is broken and will not advance

[Lyn Perrine]

To reproduce install lubuntu 17.04 today which does not have grub on it and the error box not isntalling a bootloader will not respond to user input at all.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: ubiquity 16.10.14 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 4.8.0-30.32-generic 4.8.6
Uname: Linux 4.8.0-30-generic x86_64
ApportVersion: 2.20.3-0ubuntu8
Architecture: amd64
CasperVersion: 1.379
CurrentDesktop: LXDE
Date: Mon Dec 12 20:43:13 2016
InstallCmdLine: file=/cdrom/preseed/lubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash ---
LiveMediaBuild: Lubuntu 17.04 "Zesty Zapus" - Alpha amd64 (20161212)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

I expected Lubuntu to install grub. Instead that failed bringing up this error dialog which I cannot get any useful by pressing the buttons on the GUI.

[apt-ghetto (apt-ghetto)]

Are you connected to the internet during the installation?
Do you have enabled the option "Download updates while installing"?

[Launchpad Janitor (janitor)]

[Expired for grub-installer (Ubuntu) because there has been no activity for 60 days.]