IE Mode makes the other Edge windows unusable

Just to clarify my previous post:

After investigating further:

The issue seems to be more related to launching a new window from a modal dialogue when that new window is not running in IE Enterprise Compatibility mode (rather than a separate domain) that doesn't work.

We tried a workaround which partially worked, which was to first launch a new window located in the same site (and hence still running in compatibility mode). Then from that window we redirect to the actual url we wanted to navigate to.

However there was an issue that hampered this our workaround. If you try using window.open with the url, the reference to that window that is returned from window.open() is null. If you use window.open without a url, you do get the window object returned, but if you try to manually navigate to the url you want by setting the href, then the state of the window in that reference is instantly set to closed. So whilst not the end of the world, this means that you are not able to reuse this window that you opened if the user tries to launch the new window when it was already opened.

Another issue we found was when launching a new window from a modal running in IE Enterprise Compatibility Mode, the newly launched window would launch behind the modal.

But given all of this, still the original bug raised, where a modal being opened in a site running in Edge Compatibility Mode makes all other Edge windows unusable is the biggest issue for us at the moment (trying to piece by piece modernize an old site built within modals that runs only in IE6).

Cheers