When I have to spend half an hour figuring out how to set a bookmark icon back to the right icon after using an extension, it's a bust. This extension will change the bookmark icon for a website that you want to monitor to the c4c icon, which is the kind of thing adware/malware likes to do...

Impossible to see what pages I have set up to be tracked, and no way to see if the extension is even working. Useless.

Doesnt work on fedex site. As the page reloads the extension recognizes that as a change

Does not work on Android 4 - Android 9. Right click (ie long tap) does not give c4c options, it just gives the regular Android copy, paste etc options.

they fixed the issue

"alarm Sound" not playing if i play in fullscreen game. FireFox 63.0.3 Windows 10 x64

First thing I can see with this addon is... an icon on the toolbar that does nothing.
Second is a menu that shows me how much I need to pay for something. So shows me nothing and quickly scares me away. Addon uninstalled.
Does it work? Based on other reviews - not.
There are other similar addons. Free addons. More usable addons.
One can easily create a simple script that would do the same thing. Or watch just some part of the web page.
As for an addon - this is a mistake in my eyes.
As for a pay-to-use addon it seems even bigger mistake.

v2.2.3 has problems with "Animate tab" option. Ubuntu 18.04 LTS, Firefox 63.0 x64. When "Animate tab" animates - it causes some memory leaks or read/writes on HDD, so my PC will operate slower and slower and then it will completely frozen, and the only ways to avoid this - to click on monitored tab to stop favicon animationon, or to disable "Animate tab" option at all! Something became unstable with the last FF version.