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.

Uploaded a file attachment and saw the dialog close without any errors

in the JS console.