It seems to be out of date. Doesn't work on new Firefox

Does not work on Ffox 62

not working even I am still using FF52

I only want to change the font color in my add-on. The background is sky blue and the font is white. I cannot see a thing.!

Totally broken and useless, but does not say so before install

I had stopped upgrading FF because I would lose TF&SC. Tonight I forgot and "upgraded" FF. Now my bookmark fonts are so small my old eyes can't read them easily and tire.Keep this up and I'll be forced to use Chrome....

Does not work with the current versions of Firefox, a fact not mentioned in the writeup.

It still doesn't work. Not on TB, or FF.

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Not working on Linux since FF moved to Quantum ((FF57?)

Periodically stops working. Now, April 2018 it is not fixed for weeks ...
The wanhunglo fix mentioned below works!

The thunderbird version of this addon breaks regularly rendering TB unusable because of the tiny fonts. I URGE ANYONE TO GO https://bugzilla.mozilla.org/show_bug.cgi?id=1453928 REGISTER AND UPVOTE THE BUG/COMMENT SO THAT THUNDERBIRD ADDS A FONT INCREASE OPTION BY DEFAULT

Once again not working anymore, because the id!ot author has built in a 90 day time limit after which the addon silently fails. Change build date (unix timestamp) or remove the check function in line 1382 of bootstrap.js to make it work again. Or visit wanhunglo (dot) com to download a fixed version.

Why is this addon still listed? Reported several times, this sh!t has been happening for the past three "updates" every single time!

absolutely not working extension

No funciona desde la última gran actualización

doesn't work with quantum.

Version 56, in Thunderbird 52.6.0 (64 bits) on MacOS shows no entry in tool menu neither it shows the button in the status bar. Thus, it cannot be opened !! Unusable :(

I'm using FF 52 and went as far back to v51 of this addon trying to find one that works. None did. Apart from the entry in the addon manager, there was no sign that it had installed - no toolbar option, no status bar icon. Nothing.

On Linux I can't change the font family.

Add on does not work with FF Quantum. All the advice I find on any of these pages involves files, extensions, changing this and that in your computer. You need to be a damn programmer to figure it out! Mozilla just create a simple easy to use and understand way for us to increase the size of the text in the Firefox menus. It was there before you can do it again. I have computer glasses and this is causing eye strain!!

I am so glad this was updated for Thunderbird, now if we could only get a version that works with the Waterfox browser which I just switched to today from Firefox 56 since I don't like Quantum and all my addons seem to work so far except for this one. I can't get any of the suggested fixes to work, even deleting the expiration date in the Theme Font Changer xpi file. Waterfox is suppose to open an independent browser add-on store so maybe that will help the issue.

Thanks for the hard work that goes into these addons, they make life noticeably less annoying.