You will need to create a custom bookmark in your browser. Name it something like "Custom Fields". Browser bookmarks usually point to a URL, but we're going to insert a script instead, so in the destination URL field, paste the following script:
javascript:(function(){var gaJs = document.createElement("script");gaJs.type = "text%2Fjavascript";gaJs.src = "https%3A%2F%2Fs3.amazonaws.com%2Ffreakdesign-us%2Fshopify%2Fcustom_fields%2Fs%2Ffreakdesign_custom_fields.min.js";document.getElementsByTagName("head")[0].appendChild(gaJs);})();
Now, when you are editing certain pages in Shopify, you can click your new "Custom Fields" bookmark and it will fire our script, which will reveal otherwise hidden custom fields.