I'm not certain of their use of the word "webview", nor exactly how multiple rendering windows work in Electron. In theory it should work the same as multiple t

I'm not certain of their use of the word "webview", nor exactly how multiple rendering windows work in Electron. In theory it should work the same as multiple tabs in a single Chromium instance. In any case, the Slack app is very heavy. You should be able to manage all your teams in one tab with a single instance of the app rather than a separate tab with the entire single-page app having to be loaded over and over again.