StreamLabs' Chat Box widget correctly removes a message when it's individually deleted from Twitch chat, but not when a user is banned/timed out, or when the entire chat is cleared using /clear.
This script fixes those issues, correctly removing all relevant messages.
Open the StreamLabs' Chat Box settings in the Dashboard.
Enable the setting called Enable Custom HTML/CSS.
You can leave the HTML field alone.
Copy the content of <theme>.css into the CSS field to apply that theme, since the Theme setting will be overridden.
Copy the content of custom.js into the JS field to apply the fix.
Hit the Save Settings button and you are done, note that this will refresh the Chat Box, clearing any messages that were already on there.
The license included in this repository applies only to the custom.js file, all the .css files are taken from the StreamLabs' Chat Box and are property of StreamLabs.