The plugin checks for tens of seconds to a minute, and sometimes does not work at all. Perhaps this is because the location is Russia with fenced Cheburnet, but it became impossible to use the plugin.

the add-on slows down the browser way too much. There's an unacceptable long delay between typing letters and the apperance in a text box.

Refuses to work no matter what I do. I have tried Restart Firefox, delete and reinstall the extension, Delete the extension then uninstall Firefox then reinstall Firefox then the extension. Nothing worked.

lack dictionary feature. I wanted dictionary features similar to grammarly.
reply:
Plz see grammarly what I wanted to say here ''Show definitions and synonyms
via double clicks (all sites)'' I want this feature.