We have a rather old XUL extension which we want to make sure works with Electrolysis. We will eventually migrate it to the WebExtensions API, but for now we want to use the com
Your sandboxPrototype is wrong, you are setting it to the nsIDOMWindow
, set it to the aNSIDOMWindow.gBrowser.tabContainer.childNodes[tab_index_goes_here].contentWindow
see this example on mdn: https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Language_Bindings/Components.utils.Sandbox#Example
also here is how to load in a script as file rather then doing evalInSandbox:
https://github.com/Noitidart/modtools