In this blog post from 2015 I explained how to open a modal window from an item and pass the values back, display a sucess message, etc. This page also contains an item plugin to make it easier to do the whole stuff and avoid hardcoding. I have never published this plugin. Hopefully this functionality is going to be a standard part of 5.1. Now, I was asked to make this working with a file browse item as well. I extended that example and created a new one showing how to do that with changing and clicking on a file browse item. You can see this example here. If you have an account for my workspace, you can even download the plugin and make it working in your environment. Enjoy.