I can partially replicate the situation and get out of the situation.
What worries me is that the settings page you show has no tab. Is there any theme or styles mod that made the tab not appear in the left pane?
If you have a tab, it is possible to drag the settings page into the centre workspace.
I tried to change my UI theme to the default theme (Atom Light) just like what you told me and the setting tab reappears. This apparently has to do with the theme I was using. Thanks a lot!
What theme were you using?