So after poking around for a bit I was able to get past this error with the following registry key set to "1":

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN
\FeatureControl\FEATURE_PROTOCOL_LOCKDOWN\iexplore.exe

Isn't IE support fun?

Now the save button (bug #63043) changes color but clicking it results in "SCRIPT70: Permission denied" that IE's debugger says comes from the following line in jquery.js:

proxy=function(){
    return fn.apply(context,args.concat(core_slice.call(arguments)));
};

Hints on registry keys from http://stackoverflow.com/questions/5352057/script70-permission-denied-ie9

Looks like there may be some help in the newer versions of jquery: http://bugs.jquery.com/ticket/13936

• Bug 63043 has been marked as a duplicate of this bug. ***

Got past part of the permission problem without messing with the registry (yay!) by looking at newer jQuery code and seeing how it avoided use of iframe. It is now stopping in setUpSurface.

Created attachment 14910
diff of changes to update jquery

Attached:

Updated to latest VE (which shares MW's JQuery?) and saw the problem again. Clicked IE's "Start debugging" in IE9 and wasn't able to reproduce it.

Returned to page, clicked IE's "Stop debugging" and then clicked VE's "Edit". Spinner went into infinite loop.

Now, what are the dev tools setting up to cause this behavior?

For the record, I haven't experienced this problem in weeks of messing around with VE in IE in either IE10 or IE11.

The iframe which is used to create the document is discarded and IE9 garbage collects it and wipes the document, even though we keep a pointer to the document.

Change 283427 had a related patch set uploaded (by Esanders):
Fix access of iframe-created document in IE9

https://gerrit.wikimedia.org/r/283427

Change 283427 merged by jenkins-bot:
Fix access of iframe-created document in IE9

https://gerrit.wikimedia.org/r/283427