[ActionList] showDividers bug

[josepmartins]

Description

When using the showDividers property in an ActionList component the first line doesn't show up. I was able to reproduce it and then opened the devtools and it magically rendered the divider.

This came up in the #primer-react slack channel: https://github.slack.com/archives/C01L618AEP9/p1687740736384229

cc @maraisr

Kapture.2023-06-26.at.09.44.03.mp4

Steps to reproduce

1. Add showDividers in an ActionList with 2 or more items
2. Diplay the menu and see how the first line is hidden
3. Open devtools or resize the window, the first line is displayed

Version

v35.26.0

Browser

Chrome

[siddharthkp]

From @maraisr on slack, this happens in Safari and Firefox as well, so it's not browser rendering related

[siddharthkp]

Update: We disable the divider when we expect a visible focus ring there instead. source code →

In this example, we're expecting a focus ring for some reason when there isn't one 🤔