Hi

So that we can better understand this issue, please can you provide further information about what you mean by a "Mozilla Firefox" filter"?

What do you mean by this, and how did you set it up?

If it is not an add-on,   then what is it   ?
Add-ons can be easily disabled or removed  : 3-bar menu => Add-ons => Extensions

Can you attach a screenshot?

• https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem
• use a compressed image type like PNG or JPG to save the screenshot