The bug

The four buttons at the bottom of the Play Multiplayer menu (Edit, Delete, Refresh, Cancel) are not evenly spaced. The gap between the Edit and Delete buttons is the largest, and the gap between the Refresh and Cancel buttons is the smallest.

The problem seems to persist across different window sizes and GUI scales.

For example, when playing in 1080p, with GUI scale 3, there are 30 pixels between the Edit and Delete buttons, 24 pixels between the Delete and Refresh buttons, and 18 pixels between the Refresh and Cancel buttons.

I have also just discovered that the Cancel button is slightly wider than the other three. Reducing it down to the same size as the others would fix the problem.