Broadcast Message moves Issue Board horizontal scroll bar below fold

Summary

When adding a broadcast message to Gitlab and visiting a Issue Board, the bottom horizontal scroll bar gets pushed below the fold/screen.

Steps to reproduce

  1. Create Broadcast Message
  2. Visit any Issue Board
  3. Try to scroll right to see Closed column

Example Project

Not possible, because I cannot create a broadcast message on gitlab.com

What is the current bug behavior?

Horizontal scroll bar gets pushed down

What is the expected correct behavior?

Issue Board height gets reduced to not hide horizontal scroll bar.

Relevant logs and/or screenshots

gitlabissue

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info 
System information
System:		Ubuntu 16.04
Current User:	git
Using RVM:	no
Ruby Version:	2.3.7p456
Gem Version:	2.5.2.3
Bundler Version:22
Rake Version:	12.3.0
Redis Version:	3.0.6
Git Version:	2.17.0
Sidekiq Version:5.0.5
Go Version:	go1.10 linux/amd64


GitLab information
Version:	10.7.1
Revision:	0d49bb8677
Directory:	/opt/git/gitlab
DB Adapter:	postgresql
URL:		https://example.com
HTTP Clone URL:	https://example.com/some-group/some-project.git
SSH Clone URL:	git@example.com:some-group/some-project.git
Using LDAP:	no
Using Omniauth:	yes
Omniauth Providers: kerberos


GitLab Shell
Version:	7.1.2
Repository storage paths:
  • default: /example/git-repositories Hooks: /opt/git/gitlab-shell/hooks Git: /usr/bin/git

Results of GitLab application Check

Every check was green. Very long and not related to issue.

Edited by Alex