Mined from test logs In addon-sdk/source/test/windows/test-firefox-windows.js: window.tabs.activeTab.once('ready', () => { assert.pass('window 2 tab activated'); window2 = window; rawWindow2 = viewFor(window); assert.equal(rawWindow2.content.document.title, "window 2", "Got correct raw window 2"); <- Causes CPOW warning assert.equal(rawWindow2.document.title, window2.title, "Saw correct title on window 2"); windows.open({ url: "data:text/html;charset=utf-8,<title>window 3</title>", onOpen: (window) => { assert.pass('window 3 open'); window.tabs.activeTab.once('ready', () => { assert.pass('window 3 tab activated'); window3 = window; rawWindow3 = viewFor(window); assert.equal(rawWindow3.content.document.title, "window 3", "Got correct raw window 3"); <- Causes CPOW warning assert.equal(rawWindow3.document.title, window3.title, "Saw correct title on window 3"); resolve(); }); } }); });

This is test only.

we are going to check which tests pass - and then disable all that do not to detect breakages from this point on. correcting the test suite issue across the board is a months long effort - that doesn't align with 2017 plans.