Hello! Goto about:preferences -- in the General tab you can change your Font Size like so: http://i.imgur.com/SAstO7b.png

Firefox generally following your Windows Text Size setting (e.g., 100%, 125%, 150%) as part of its support for high DPI displays. You can override that and enlarge ALL text in Firefox (toolbars and content) using the following method:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button accepting the risk.

(2) In the filter box, type or paste pix and pause while the list is filtered

(3) Double-click layout.css.devPixelsPerPx and change its value to 1.25 and click OK, which corresponds to 125% font size in Windows display settings. The toolbar area should enlarge after a few moments. Too small? Try 1.5 and see whether that suits you better. And so on.

Important: Do not go below 1.0 because it may become too tiny to edit.

Thank you. That helped!

You may want to go to there page https://addons.mozilla.org/en-GB/firefox/addon/theme-font-size-changer/ it was just update an hour ago. New Version but does not say compatible with 57 Might want to contact them support@barisderin.com

Please let us know if this solved your issue or if need further assistance.

Theme Font & Size Changer is compatible with Firefox 57.

See this screenshot :

Yes, the extension is available now, but is barely functional. This is what is on their page:

Theme Font & Size Changer

Theme Font & Size Changer instantly changes the font family, font size, font color, font style and background color of main interface for Firefox and Thunderbird. Theme Color Theme Background Color Theme Text Color Your Attention Needed Please!

Because of the new extension system on Firefox, most of the functionality of the Theme Font & Size Changer is not available any more. You can read more about this new system here.

Please help us by commenting our survey about future of Theme Font & Size Changer by clicking below link. It only includes 5 questions for you.

Theme Font & Size Changer Survey

We need your comments to determine future of Theme Font Size Changer by the survey. Thank you for your help and feedback.

At the bottom it says :

We need your comments to determine future of Theme Font Size Changer by the survey. Thank you for your help and feedback.

Maybe you'd like to do just that  ?

I'm really hard of seeing and don't want to stay at FF 56, but I absolutely need Theme Font & Style Changer. The add-on update is not doing anything on font size, just colors, in FF 57; so I've rolled back to FF 56. Is there an alternative to Theme Font & Style Changer out there? On a Mac so the Widows solutions are of no use, btw. Thanks!

Hi pcbjr, did you try the setting adjustment in this post: https://support.mozilla.org/questions/1184537#answer-1028032

jscher2000 said

Hi pcbjr, did you try the setting adjustment in this post: https://support.mozilla.org/questions/1184537#answer-1028032

Yes and on the Mac it made things smaller - in each direction ...  :~(

pcbjr said

jscher2000 said

Hi pcbjr, did you try the setting adjustment in this post: https://support.mozilla.org/questions/1184537#answer-1028032

Yes and on the Mac it made things smaller - in each direction ...  :~(

How high did you go? Perhaps on a retina display you need to get above 2.0 to have any effect.

jscher2000 said

pcbjr said

jscher2000 said

Hi pcbjr, did you try the setting adjustment in this post: https://support.mozilla.org/questions/1184537#answer-1028032

Yes and on the Mac it made things smaller - in each direction ...  :~(

How high did you go? Perhaps on a retina display you need to get above 2.0 to have any effect.

Good thought - it is a brand new iMac. I'll check it out after dinner!

this is what worked for me ( opensuse 42.1) go to the folder .mozilla/firefox located in the homedirectory for linux. from there go to your profile folder - for example poab5o41.default on my pc. create the folder chrome and create the file userChrome.css with the following codelines - adjust the fontsize by changing the line font-size:17px

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

menubar, menubutton, menulist, menu, menuitem, toolbar, tab, tree, tooltip /*,textbox*/ {

 font-family: Segoe UI, SegoeUI, calibri, verdana, helvetica, tahoma, Arial !important;
 font-size: 17px !important;

}

http://i63.tinypic.com/242a4g8.png

Happy112 said

Theme Font & Size Changer is compatible with Firefox 57. See this screenshot :

Thanks, but where do we find this?

I downloaded the theme and font size changer, but don't see where to change the font nor do I see the page in your screen shot.

THANK YOU.

Maybe if we all messaged the TFSC extension creator, he will speed up updates to make it work in FF 57. FF 57 is supposed to be faster, but I haven't noticed any difference there. I didn't want these problems on my other Windows 10 computer, so I turned off auto updates on FF. It updated anyway to FF57 this morning. Now I have to find a replacement for the Flash Stopper extension to prevent auto-play on websites. But that's another thread for another day.

Ladyjay12 said

Maybe if we all messaged the TFSC extension creator, he will speed up updates to make it work in FF 57. FF 57 is supposed to be faster, but I haven't noticed any difference there. I didn't want these problems on my other Windows 10 computer, so I turned off auto updates on FF. It updated anyway to FF57 this morning. Now I have to find a replacement for the Flash Stopper extension to prevent auto-play on websites. But that's another thread for another day.

Yes - please message them. I have; it seems like what they are looking for.

pcbjr said

Ladyjay12 said

Maybe if we all messaged the TFSC extension creator, he will speed up updates to make it work in FF 57. FF 57 is supposed to be faster, but I haven't noticed any difference there. I didn't want these problems on my other Windows 10 computer, so I turned off auto updates on FF. It updated anyway to FF57 this morning. Now I have to find a replacement for the Flash Stopper extension to prevent auto-play on websites. But that's another thread for another day.

Yes - please message them. I have; it seems like what they are looking for.

Where do write please?

silversolara said

Where do write please?

See under 'More Information' :

https://addons.mozilla.org/en-GB/firefox/addon/theme-font-size-changer/

Happy112 said

silversolara said

Where do write please?

See under 'More Information' :

https://addons.mozilla.org/en-GB/firefox/addon/theme-font-size-changer/

THANKS...just wrote.

jscher2000 said

(3) Double-click layout.css.devPixelsPerPx and change its value to 1.25

Using layout.css.devPixelsPerPx 1.25 isn't sulution for me as it also increases font size in displayed web pages. I want to change font size in FF toolbars and menus ONLY.

In previous versions of FF I used Theme Font & Size Changer Addon but in FF57 it isn't able to change font size. Author off addon informed about that.

Is it so hard for Mozilla developers to add separate font size changing feature working ONLY for toolbars and menus?!