Controlled by Extension option in Tabs is disabled

[SteveRoseWgtn]

I've just downloaded and installed version 1.15.1147.64 on Windows 10.
I want to enable the option called "Controlled by Extension". It is in Settings, Tabs, indented below Start Page.

Issue: "Controlled by Extension" is disabled, and there doesn't seem to be a way to enable it. Is this a bug, or have I missed something?

Other info
My plan is to migrate from Chrome where I use the Tabs Outliner extension. That extension needs to control new tabs, and that's why I want to select Controlled by Extension.
I had tried version 1.10 some time ago and then uninstalled it, so I think that this is a new install with no previous settings carried over.
I went through the initial setup of selecting tab bar position, background, etc, and immediately installed these extensions: Tabs Outliner, Ghostery – Privacy Ad Blocker, uBlock Origin, Copy Plain Text, and Percipio.
Then I went to the Settings to change the Controlled by Extension option, and found that it's disabled.
Restarting Vivaldi hasn't helped.

[Ornorm]

@steverosewgtn Hello SteveRose,
welcome to Vivaldi. I hope you'll have a nice experience with this browser.
Regarding your "Controlled by Extension" issue, you first need to download/activate an extension which can take control on the start page.
I just tried with Momentum installed (as an example) and it works fine (because Momentum interferes with the Start Page of Vivaldi) :

If the extension isn't installed/activated, the option remains indeed inactive.
So, this option only concern the control of the Start Page of Vivaldi.
The other extensions you mentioned should just work fine even without this "Controlled by Extension" option.
I hope this helps.
Enjoy Vivaldi (I'm quite sure you won't regret it).

[pafflick]

@steverosewgtn The "Start Page > Controlled by Extension" option is only available when you have an extension that is capable of controlling the new tab page (called "Start Page" here). From what I saw in the overview video, "Tabs Outliner" offers no such functionality, thus the aforementioned option is disabled. I don't know why are you trying to enable it since the extension seems to work fine in Vivaldi. Is there something that is not working for you?

[SteveRoseWgtn]

Thanks for your explanations @ornorm and @pafflick. I'm glad it's working as expected.

I'm not able to persuade the Tabs Outliner extension to display its own window, and thought the disabled option might be required. The other extensions seem to be working fine. However I only intended to use Tabs Outliner briefly. I thought I might be able to easily copy groups of tabs over by copying its data across from Chrome, without using bookmarks, but I'll use one of the other easy ways.

I'm looking forward to using Vivaldi. It looks to be one of the best browsers, very nice job everyone.