WebBrowser Control: OLECMDID_COPY and 64 bit doesn't work

[Philip Losch]

We have a problem with our WebBrowser control when we use a 64-bit
build: copy and cut operations won't work. This happens under Win7,
Vista and WinXP.
Copy chosen from the browser context menu and Ctrl-C won't work,
however all other commands like Select all, Undo etc. perform fine.
Under any 32-bit build everything works as expectec.

When I manually call copy or cut like this:

lpOleCommandTarget->Exec(NULL, OLECMDID_COPY, OLECMDEXECOPT_DODEFAULT,
NULL,NULL);

the result value is CO_E_NOTINITIALIZED, which doesn't make any sense
as all our threads are initialized with
CoInitializeEx(NULL,COINIT_APARTMENTTHREADED);
Also, when I directly try to call another CoInitialize before Exec the
return value for CoInitialize is S_FALSE, which confirms that the call
has been made before.

Researching the web a couple sites pointed to security settings, but
all of them are set to factory defaults and this is only a local HTML
page (a file) that is displayed.

Thanks in advance for any pointers!