Steps to reproduce:
Install FF ublock origin. Enable "I am an advanced user". Click the ublock Origin icon in any web page -- the popup renders in "portrait" mode with an obscuring scroll bar. This only happens when uBlock does not recognize it has horizontal space to work with.
I submitted this as a bug report to uBlock-issues and was suggested to use the dev build. This also did not resolve the issue.

Expected behavior:
The popup should open in standard / landscape mode:

Orion, OS version; hardware type:
All versions I've tried since initial beta, currently 0.99.122-beta.
ublock versions 1.40, 1.44.4, 1.45.3rc6