I just looked in filer and it seems to me that you are trying to pass size set to all images in the directory_listing just to have it when the popup is closed so you can open cropduster window. If this what you're trying then it might be easier to exclude filer from this story and add some javascript here(since you already have size_set context variable) that can check if a new value was pasted in the field value, and then open cropduster window.