Okay... I decided to try to capture a video of this again. This time rather than hoping it happens while playing a game, I just opened and canceled the window over and over until it happened. In this case, it happened on the fourth attempt. You will see clicking the + to warm up a reliever makes the widget disappear.
I couldn't figure out a way to embed the video in the post, so here is a link to an unlisted Youtube upload.
https://www.youtube.com/watch?v=HYwZGLneJm4