If you encounter some applications freezing or taking a long time to start while using i3, I think in particular about Skype, Discord, CMST (Connman QT GUI), Hexchat, … then may be here is a solution for you. Those app do not appreciate when the desktop does not have any notification daemon running. So you might just install and start one when i3 starts.

So I’ve just installed lxqt-notificationd. Then you can start it from i3’s config file:

exec --no-startup-id lxqt-notificationd

Now all my applications work like a charm, and I’ve no reason whatsoever to temporarily switch to XFCE4.