Disappearing controls on narrow windows

Summary

When the web browser window is narrower than about 755 pixels, the controls disappear. This is particularly a problem when viewing a branch and trying to create a new merge request. May be linked to the sidebar controls vanishing on narrow pages.

Steps to reproduce

. View any branch that has not yet been merged to master - see 'Create Merge Request' button . Change web browser width to narrower than ~755px - see button vanish

Example Project

https://gitlab.com/laubai/testproject/commits/mergetest

What is the current bug behavior?

'Create Merge Request' button disappears instead of shuffling underneath other UI elements.

What is the expected correct behavior?

UI button moves to a different location rather than vanishing entirely.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com