This Addon does not have an icon that is always visible. Only a fingerprint icon is displayed in the adress bar when some canvas data was faked for the web page. You can test at http://kkapsner.github.io/CanvasBlocker/test/test.html

If you still think that it's not working properly try version 0.4.4a and open a new issue at https://github.com/kkapsner/CanvasBlocker/issues

EDIT: no problem. Glad that it works for you.

Yes, in the standard settings of CB the fingerprint that is produced with CB is quite unique but not persistent. That means the browser itself (and therefore you) cannot be indentified by it. (The same issue was reportet on github: https://github.com/kkapsner/CanvasBlocker/issues/154 - if you want further informations you can explore the issues there or post a new one.)

Also there are a lot of options which change the behaviour of CB (just mark the expert mode). If you want a less unique fingerprint you can use the "white" random number generator which will result in fingerprints similar to those of the Tor browser.

I do not see any errors. Please open an issue at https://github.com/kkapsner/CanvasBlocker/issues where you can describe the scenario when you see the errors.

I currently face weird problems. Please open an issue at https://github.com/kkapsner/CanvasBlocker/issues with all your details (versions, settings, etc.) so that I can find the root cause.

EDIT: please try version 0.4.4

The whitelisting was hidden by the last release. You can whitelist by setting the desired blocking mode for the URL specifically. If you want to whitelist an URL just give it an "allow everything". You can still whitelist a site from the notifications. I should definitely clarify the description...

Adding an URL specific block mode:
go to options, click on the triangle next to the blocking mode, enter the domain you want to whitelist, click on the plus, now you can set the blocking mode for the domain.

PS: you can still enter something in the white list by checking expert mode, open the export settings page and entering something in the whitelist field.

EDIT: Is the screenshot of the settings not explanatory enough?
EDIT2: It's easier for us to communicate on github. If you have any questions - just open an issue. Here the communication is slow and not relyable.

EDIT3: please try version 0.4.4 - there the whitelist is available again.

Can you please file an issue at https://github.com/kkapsner/CanvasBlocker/issues with more details. I already know that there are problem but I'm not able to spot them because I never had a reproduction scenario.

EDIT: Have you tried any of the Beta versions? https://github.com/kkapsner/CanvasBlocker/releases/
EDIT: Please try version 0.4.4

I will look into this issue (progress can be seen here: https://github.com/kkapsner/CanvasBlocker/issues/161). The faking is working fine on https://browserleaks.com/canvas

EDIT: They are using a very big canvas (400 000 pixels) to do the fingerprinting. It works fine if you disable the "Maximal fake size" ("Maximale Vortäuschgröße") setting. I will adjust the recommendation accordingly.

This issue was already reported to me. But I'm not able to reproduce it on my end. Please create a new issue on github with the informations to reproduce the problem (Firefox version, installed Addons, CB settings, URL to the not working image and if the problem is still present when a fresh profile is used): https://github.com/kkapsner/CanvasBlocker/issues/new