I've seeing the FAQ and this forum but I don't find anything about it. I know it exists as it is shown in my genie 17g, but I don't know how to make it work. Thanks.
First, please make sure you're using FM in windowed mode. Then hover over (i) icon next to player's name, and GS customized window should pop up. Sometimes it doesn't work, I hope to fix it within few days.
