Cannot set tiling background for desktop

The Ubuntu settings app used to allow choosing how the background image would fit the window (tiled, stretched, centered). It no longer offers any choices, backgrounds are always stretched.

(Other approaches, like alt-clicking on an image in Firefox, still allow me to set a tiled background, so clearly the system is still capable of it, but it has vanished from the settings UI.)

The settings app also seems generally sparser and less functional than before, which is off-putting.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-control-center 1:3.28.2-0ubuntu0.18.04.2
ProcVersionSignature: Ubuntu 4.15.0-42.45-generic 4.15.18
Uname: Linux 4.15.0-42-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Dec 6 13:38:25 2018
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-trusty-amd64-osp1-20150720-0
EcryptfsInUse: Yes
ExecutablePath: /usr/bin/gnome-control-center
InstallationDate: Installed on 2016-04-15 (965 days ago)
InstallationMedia: Ubuntu 14.04 "Trusty" - Build amd64 LIVE Binary 20150720-04:06
SourcePackage: gnome-control-center
UpgradeStatus: Upgraded to bionic on 2018-11-08 (28 days ago)