Edit: See my next message as I misunderstood the question.
Yes, passing NULL as the ShellExecute verb should achieve that (assuming it is also how you have configured Opus) as it will do exactly the same thing as double-clicking a folder on the Desktop, for example. (Passing "explore" or "open" verbs is not always the same as double-clicking things; passing NULL is.)
[quote="steje"]I think the option Nudel is referring to is highlighted below (global_explorer_replacement):[/quote]Yep.
Yes, passing NULL as the ShellExecute verb should achieve that (assuming it is also how you have configured Opus) as it will do exactly the same thing as double-clicking a folder on the Desktop, for example. (Passing "explore" or "open" verbs is not always the same as double-clicking things; passing NULL is.)[/quote]
Having re-read what you asked, I was talking rubbish. Without manually editing the registry there is no way to make Opus react to folder launches/double-clicks by changing the current directory in an existing window.
You can either:
[ul][li]Open a new tab in an existing window
or:
[/li]
[li]Open a new window.[/li][/ul]
That's how it's always been, though. (Except when the only option was the second one.)
I'm still confused about how it could ever have worked differently as people say it did (unless the registry was edited).
Watch this space, though. Jon said he's going to dig out 9.0.0.6 and see exactly what happens with it.
(None of what I've said in this reply changes what I said about passing NULL as the verb, though. That's still the right thing to do if you want Opus -- or whatever is the default folder handler -- to act as if a folder was double-clicked. That is separate to the question of how to make Opus change the current directory when a folder is double-clicked.)
I didn't realise until now that FileBox eXtender adds its menu to Opus itself (among other things). Now it makes sense why you all want it to change the current directory! I don't think you're crazy anymore. 
Until now I thought it just affected the File Open (etc.) dialogs and made it so that if you selected from the menu it would launch the folder into Explorer or Opus (etc.).
Does FileBox eXtender have special code to detect and attach to Opus windows or does it use something generic (like seeing if the titlebar is a valid path)? If there's already Opus-specific code in FileBox eXtender then I think it should be easy to work out a method to make it all work with some simple changes to Opus and/or FileBox eXtender.
Hello,
I just got an answer from Jonathan Potter to my "official" request about this issue:
As also suggested by Jonathan I will use the previous version (9.0.0.6) until the next version is available.
Thanks for your help.
Regards
Michael