I have carried out a search on my sub folders and when the result list is shown it shows which folder the email is in. It is in a highlighted box below the email title. If it is a sub folder it only shows the subfolder not the "main" folder that the sub folder is in i.e ...../subfolder name.
Clicking on the email title or the shown highlighted folder name opens the email.
The folder name is shown below the sender/recipient, date etc. or as you have called it, the header. Again it only shows the actual folder that the email is in, not the "main" folder if it is in a sub folder.
I do use the webmail system but not on a regular basis so I have no idea whether or not it previously showed the "Main" folder followed by the sub-folder in the email below the sender/recipient etc. or whether it has always just shown the actual folder the searched for email is in.
Thanks for looking at that @gg30340 i'm waiting to see what the team says about this. I'm not seeing any subfolders at all. At one time it did have all the levels but it then defaulted to just one level below as you see. I'm not seeing anything at present. I've checked it on 3 different browsers and its the same no matter what. Perhaps its a case of me using the wrong browsers. I also checked it on gmail in my phone and it shows nothing either but i've never checked those before on the phone.