**Update 10 August 2019: version 1.2 now works with the new Twitter UI**

It didn't stop working. The extension is not built to handle the new Twitter interface (currently being trialed) so it has no effect there. This will get fixed.

In the meantime, if you manually chose the new Twitter interface, clear Twitter cookies and log in again. It will reset the interface to the old Twitter and the extension will work again.