Drupal 8 Bootstrap Theme Background "transparent" (e.g. offcanvas-lining visible) I have installed the Drupal 8 Bootstrap Theme (version 8.x-3.0-rc2) on a newly setup site. When I logout and view the page everything looks as I would expect it. But while I am logged in when I click on "Back to Site" in the top left corner then I only see a background ofbackground-color: #333 which is being set by a class named .offcanvas-lining. This makes working with the theme almost impossible because the text and headers have the same color and so the text is invisible.

I could probably override that somehow but I would like to understand if this is an issue with the Drupal 8 theme or if I have made a mistake when I setup the theme.

What is this offcanvas-lining element doing and why am I seeing its background rather then the usual white bootstrap background which is the default.
Looks like this was being caused by the "Settings Tray" module which was added in Drupal 8 and which I had activated. Deactivating the module has fixed the issue for me.

It seems other people also have this issue with other themes: https://www.drupal.org/node/2819091