I clicked on the Libraries tab in the web IDE and typed in ITEADLIB_NEXTION. It then says “Loading…” but never does… It’s been three hours now. I tried refreshing the browser window to no avail. Is Particle down or something?
That’s a known issue with the browser cache.
You can try incognito mode or clear the Web IDE cache and if required the browser cache too.
Thanks! Clearing the cache didn’t work but incognito mode did. This is with Chrome Version 47.0.2526.106 m in 32 bit XP SP3.