[Plugin: Collapsing Categories] expand on hover

I was in this forum a couple of weeks ago and found code that I could add to the plugin file to have the categories expand when you hover on them. I’ve had to make some changes here and there and I’ve lost that customization. I can’t find the code anymore. Can someone tell me how to do this again? Thanks so much. Please be specific because I’m still learning. Thanks very much.

https://www.ads-software.com/extend/plugins/collapsing-categories/