please check the screenshot

Is this a new issue with your site, or has this always been a problem with Firefox? One method to distinguish a settings / add-ons problem from a core Firefox problem is:

New Profile Test

This takes about 3 minutes, plus the time to test your site.

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Take a quick glance at the page and make a mental note of which Profile has this notation: This is the profile in use and it cannot be deleted. That is your current default profile.

Click the "Create a New Profile" button, then click Next. Assign a name like Feb2022, ignore the option to relocate the profile folder, and click the Finish button.

Firefox will switch your default profile to the new one, so click the Set as Default Profile button for your regular one to avoid an unwanted surprise at your next startup.

Scroll down to Feb2022 and click its Launch profile in new browser button.

Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system to get a clean test.

Does the comment box work any better in the new profile?

When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (Feb2022 will remain available for future testing.)

Do you mean that you can't set focus to the text area and get a cursor by clicking in it with the mouse ?

If that is the case then try to use the tab key to see if that allows to focus this text area.

You can possibly check in the Inspector what element is selected if you check this via the right-click context menu.

You can right-click and select "Inspect" to open the built-in Inspector with this element selected.

• https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Examine_and_edit_HTML