Moved suggestion/minor bug here to keep it easily trackable.
Steps to reproduce:
Present in all current orion version.
The option is falling under the bookmarks header right now. Suggestion is to move it to the tabs header as it is about tab navigation.
Here is the corresponding option in safari, which is correctly categorized.
Orion, OS version; hardware type:
Version 0.99.114-beta (WebKit 614.1.12)