When you haven't interacted with or used the chat bot.
Want to get rid of the chat window? If your screen looks like this, just click on the small gray x to the top right of the chat:
When you used the chat bot, but now you're done.
If you clicked on the little chat bot icon at the bottom right of your screen, it opens up to look something like this:
While you can't get rid of the chat icon entirely, just click on the little blue arrow to minimize the chat screen: