Opening a classic module page without freedom shell

So, in a new demo instance of Creatio, you can go to a message template and click the edit template button. When you do this, you will notice that a new tab is opened and a full page content panel is opened.  This is actually a classic module, but you will notice in the url for the page, that it's using the classic shell (/Nui instead of /shell).  Really, it opens without any shell at all.

I have a custom version of the same content editor, but when we open this module page the same way, you can see that it initially pops to the right url (similar to the demo instance), but it is immediately routed to a /shell url and stops there. 

I don't know if there's some internal router exception for the default editor module in Creatio that allows for it to open under the classic shell or if there's something else I'm missing.  In debugging the code, I open the page the same way, simply calling window.open and passing in the url with the same structure. 

For those familiar with this module, it's not entity bound, so you can add an exception in UI management. Wouldn't matter anyway, since the default creatio editor isn't doing this either (url would reflect the /shell path, instead of the /Nui classic path).

Anyone have any experience with this?

Jeremy