Preview.ResolveSite and the disabled Shared Layout button in Sitecore Experience Editor

After installing some Sitecore 8.1 sites, we noticed something weird in one of the new features in the experience editor: the final/shared layout button, which quite some editors were waiting for.

The symptoms:

The Final/Shared button is disabled.

Some more testing came up with the following results;

• It happened on some Sitecore 8.1 installations, but not on all of them
• It happened on all browsers, on different client machines
• It happened only if we went from the LaunchPad to the Content Editor and then via the Publish ribbon to the Eperience Editor
• It did not happen if we went from the LaunchPad immediately to the Experience Editor - and strangely enough once we had visited the Experience Editor this way the button was always enabled throughout the entire session

It took us quite a while and help from Sitecore Support (thanks Yuriy) to figure it out, but then they pointed us at a the Preview.ResolveSite setting. A small explanation is also found at Kirkegaard's blog.

The preview resolving settings

On a multisite solution, when one opens a page in the Experience Editor, by default, Sitecore resolves the corresponding site using the value of the Preview.DefaultSite setting from the \App_Config\Sitecore.config file. The default value there is "website".

However if one sets Preview.ResolveSite setting value to "true" (it is located in the same file and by default it is "false"), Sitecore tries to resolve the root item and the context site based on the current content language and the path to the item. If Sitecore cannot resolve the context site, it uses the site that is specified in the Preview.DefaultSite setting.

So, if Sitecore renders the page on the solution in context of the "website", the Final Layout button is disabled. Why that happens is still a mystery as the rest of the Experience Editor is working fine.

But anyway: setting the Preview.ResolveSite to true fixed the issue.