LibreOffice’s spin buttons have the wrong background

[Amr Ibrahim]

Steps:
1. Start Writer
2. Go to Tools -> Options -> LibreOffice -> General
3. You will see an input field with + and - buttons

The buttons are not properly themed in Ambiance:
1. The - button has no left border
2. The + button has an extra right border
3. There is no hover effect (only touching without pressing the button)

All those three issues do not exist in Adwaita.

See the attached screencast.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: light-themes 16.10+18.04.20180328-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
Uname: Linux 4.15.0-13-generic x86_64
ApportVersion: 2.20.9-0ubuntu4
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Apr 16 15:37:38 2018
InstallationDate: Installed on 2017-10-02 (195 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Beta amd64 (20170930)
PackageArchitecture: all
SourcePackage: ubuntu-themes
UpgradeStatus: Upgraded to bionic on 2018-03-27 (19 days ago)

[Launchpad Janitor (janitor)]

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

[Adolfo Jayme Barrientos (fitojb)]

This is actually a LibreOffice bug. Red Hat’s Caolán is hard at work at improving LO’s integration with Gtk+ in a gradual process he christened “welding”, which you’ll see when we release version 6.1 in August.

[Amr Ibrahim (amribrahim1987)]

It's still affecting Ambiance in:
Version: 6.2.4.2
Build ID: 1:6.2.4-0ubuntu0.18.04.1~lo1