HTML5 video player dropdown is interrupted by other options

Steps to reproduce:

1. Go to any HTML video player, ex https://www.wowza.com/testplayers
2. Click these arrows on the right side to drop down video options
3. Observe that the playback speed options are blocked by an extension's option (uBlock origin) as well as "View page source".

Expected behavior:

Orion, OS version; hardware type:
Version 0.99.109.1.6-beta (WebKit 613.1.12)