When you double-click on a unselected content, it is just selected
you have to double-click on a selected content to open it

For historian, it is the same as the famous "triple click on sitemap tool".

The problem is at first click a synchronous request is sent, so the second click is ignored.

Two ways for correcting :
1) as in the sitemap tool, way a little bit on a single click before starting the synchronous request
2) use an asynchronous request

(the request is the one for the contentmessagetargetfactory)