Can't get filter to work

Hello Tim,
first of all thanks for this awesome plug-in, I really appreciate that it is so simple and customizable.
As a matter of fact I tried to use the filters to customize my timeline, and found out that all the filters work out of the box, except the latest_tweets_render_text one. If I paste it in my functions.php file nothing happens.
I’m not a coder and I’m probably doing something wrong, so I’d be glad if you – or any other user – could point me to the right direction.

Thanks in advance.

https://www.ads-software.com/plugins/latest-tweets-widget/