After installing Tab Center, tabs are moved on the side in the unfocused windows

[SoftVision-CiprianMuresan]

[Affected versions]:

• Firefox 51.0.1 and above
• Tab Center 1.29.0

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• The "xpinstall.signatures.required" is set to "false" on a new clean profile.
• Have at least 2 windows opened.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites.
2. Navigate to about:addons->Extensions and click the gearwheel icon.
3. Choose to "Install Add-on From File" and select the latest Tab Center xpi.
4. Focus the 2nd window and observe the tabs position.

[Expected result]:

• Tabs are on top.

[Actual result]:

• Tabs were moved to the side.

[Notes]:

• Here is a screen recording of the issue:

[ericawright]

Yes, we had decided on this behavior for the test pilot users since we assumed they would be prepared for the change. I'm open to hearing differently though....

[SoftVision-CiprianMuresan]

It makes sense, but I think it kinda defeats the purpose of the Tour if we change all windows except the one where we're installing from.

To be honest, it was a bit of a distraction for me to see the background window show the tabs to the side, and my attention was drawn to that and not the Tour which was opened.

I can think of two possible solutions for this:

• Leave all windows unaffected so we can let the user to take this decision for each window that he has opened, because the Tour already explains how to move tabs on the side.

Pros: the user has more control over the change. Cons: the user has to repeat the action on all windows.

• Leave all windows unchanged until the "Show me how it works" button is clicked.

Pros: the user doesn't have to repeat the action on all windows. Cons: the user has less control over the change, but it's expected

To me, the latter seems like a more natural transition.