What is the problem?

When using the "basic form" to add a citation, if you open the special character menu there is a small part at the top of the window which you cannot interact with.

There appears to be <div> blocking interaction. It is highlighted in the below screenshot.

Steps to reproduce problem

1. Edit any article with VisualEditor
2. Click "Cite"
3. In the "Add citation" popup that appears, click "Manual" and then "Basic form"
4. In the "Reference" popup that appears, click the Special Character menu (Ω)
5. Try to interact with the top part of the menu, such as by trying to drag the scroll bar down

Environment

Browser: Firefox 78, Chromium 87, IE11
Wiki(s): https://en.wikipedia.org VisualEditor 0.1.2 (13f8d7d) 01:25, 18 May 2021.