Shell extention activation on application's startup

Hello, beatiful world!

I am exploring Shell extension (and COM Object, in gereral) on Windows XP. And I've seen, that some applications, like Dropbox, are somehow "activates" shell extensions after application's launch. I was wondering how it may be done.

Here is some advanced information I've been able to get regarding Dropbox:
There are two interfaces (IContextMenu and IShellIconOverlayIdentifier) that, according to registry (and tool ShellExView), are implemented by in-process server DropboxExt.14.dll. Howerer, Dropbox's overlay icons and context menu items appears only if application itself (Dropbox.exe) is running. May be there is a way to somehow "bridge" implementation from *.dll to *.exe when the latter is running?

Thanks!

Application may (un)register shell extension on the fly. Use registry monitor to have a proof on that.

Thanks, Игорь!

That was really quick answer! Here as the Regmon's results that were taken at Dropbox's startup: http://i56.tinypic.com/312z7kp.png

Unfortunately I don't see any values that would look like Dropbox extension's CLSID {FB314ED9-A251-47B7-93E1-CDD82E34AF8B}.

When Dropbox is closing there is no writes into registry at all.

Maybe I've missed something, or there is another way?

Then the extension just does not add menu item while main exe is off.