Dual-pane Mode not working

When toggle dual-pane mode, the left side would extend out to full screen and unable to navigate after that.

MacOS Big Sur (11.0.1)
Screenshot 2020-12-07 at 12.11.10

I am having the exact same issue after upgrading to Big Sur. Also, checking the preference pane for Total Finder, I see a lot less options than the ones found in the instructions. Have checked for updates and am running the latest version of Total Finder (1.12.3)

See this post

Looked through the post … changed settings as suggested … problem still persists