UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.75 Safari/537.36

Steps to reproduce the problem:
1. Open Chrome and maximize the window.
2. Close button etc. is much smaller.
3. Return window to normal mode and the buttons are the correct size.

What is the expected behavior?
When the window is maximized, the close etc. buttons should be the same size as when the window is normal.

What went wrong?
Close etc. buttons are not keeping a consistent size.

Did this work before? N/A 

Chrome version: 68.0.3440.75  Channel: stable
OS Version: Ubuntu 18.04
Flash Version: 

I don't remember seeing this issue in Ubuntu 17.10 or earlier. However, I'm not sure if this is related to Ubuntu 18.04 or a new version of Chrome.