Enable AJAX blocking behavior (JavaScript injection)?

Hello Yann, will have to dig into it. My guess so far is that ajax requests are not interactive with the end user most of the time, what i mean is you use it to retrieve content to be used by the pages locally. So an error page will not be displayed by the return of an ajax call. The feature seems to respond with a javascript which will be interpreted by the browser and lauching a popup with the error message.