Steps to repro:

1. Open Unity;
2. Create new project;
3. Expand 'Help' context menu tab;
4. Observe element's rendering inside the 'Help' context menu.

Actual result:
Two segment separator line are rendered in Help context menu tab under 'Report a Bug...'. See attached actual.png screenshot.

Regression introduced in Unity 5.6.0b5.

Expected result:
Either one segment separator line should be rendered in Help context menu tab under 'Report a Bug...'. or the window should end at that point. See attached expected.png screenshot.

Notes:
- Reproducible in 5.6.0b5; not reproducible in 5.6.0b4,
- Reproducible on both OSX 10.12.2 and Windows 10.