Cannot block elements without closing popup UI

[Ross]

Environment

ABP 0.9.11.1849
Edge 40 / Windows 10

How to reproduce

1. Visit ​https://www.google.com.
2. Attempt to block the text field via Block element in popup UI.
3. Repeat Steps 1-2 with ​https://arstechnica.co.uk/
4. Repeat Steps 1-2 with ​https://www.reddit.com/

Observed behaviour

In general: The highlight does not appear while the popup UI is open.
Google: The highlight does not appear at all even when page is focused/popup is closed. Cannot block elements.
Arstechnica: The highlight only appears after the page is focused/popup is closed. Can block elements.
Reddit: The highlight only appears after the page is focused/popup is closed. Can block elements.

Expected behaviour

In Chrome, the user does not have to refocus the page and can highlight elements via mouse movement while the popup UI is open.