Steps to reproduce:
- Log into a system running Ubuntu 18.04 using XFCE 4.12.
- Create a LibreOffice window and a Nightly 66.0a1 window.
- Customize Nightly and un-check Title Bar at the bottom.
- Customize Nightly and check Title Bar at the bottom.
The window controls (Minimize, Maximize, Close) are always the same for every application.
LibreOffice and Nightly have the same window controls.
LibreOffice and Nightly have different window controls because Nightly changed.
See the attached screen shot showing the results after step 4).