Once upon a time, we were trying to make all our backbone "classes" work more like classes in many other languages, and we added a `_super()` function which attempts to automatically resolve the extended prototype. When this fails, it has a habit of infinitely recursing. I hit this recently attempting to upload a file attachment on release-5.0.x. I'm not sure if there's a change in the code or a change with how babel is transpiling something. In these cases, the solution is to replace the call with an explicit call to the parent prototype method. Testing Done: Uploaded a file attachment and saw the dialog close without any errors in the JS console.