I have a multi-select page attribute which contains a large list of values. The attribute list is used in various places on the site such as in the dashboard and in the page composer when creating or editing a page. I want to give the option to select all so if the first option is checked then all checkboxes are checked. This is just a bit of easy javascript. The problem I'm having is getting my javascript to load globally. I have tried registering it in the package controller and I have added it as a footer item in the on_start method in my controller. I can see the javascript being loaded into the page but the javascript is not being triggered in the new page composer screen. It works in the dashboard just fine. How can I get my custom javascript to be available when opening a page for editing in composer?