Right, there is no way to disable this addon!? It doesn’t appear in the list of addons! The only thing I can do is remove it from the top RHS of the screen and that didn’t fix it.
I’m sorry, you seem to me to be some sort of “clearing house”? You don’t actually provide support to the “Font Size Changer”?
Wouldn’t it be better I I actually address my problem directly to them?
I STILL don’t have any icons on my Yahoo (and other Apps).
In fact I have NOW lost the “Delete” “Move” “Spam” and “More” boxes too 
Regards,
Louis
There are 10 kinds of people in the world:- People who know binary and people who don’t.
Sending you another example, this time of YOUR own site. This the end of one post and the start of the next…
Regards,
Louis
There are 10 kinds of people in the world:- People who know binary and people who don’t.
Are you saying the “Font Size Changer” Add-on is causing this? Where did you install it from?
20 years with Yahoo - no problems. Install Font Size Changer - No icons… Draw your own conclusion.
I don’t have a clue where I installed it from. It came up, I thought it looked good, I installed it and have regretted it ever since 
Sorry, I didn’t attach the example from your site…
There are 10 kinds of people in the world:- People who know binary and people who don’t.
What is the exact name of the add-on? Is it https://addons.mozilla.org/en-US/firefox/addon/theme-font-size-changer/?
Have you tried https://support.mozilla.org/en-US/kb/add-ons-and-extensions-faq#w_how-do-i-disable-or-uninstall-an-add-on ?
This is the requester that comes up when I click on its’ icon…
If this is a different one then I apologise… There are 10 kinds of people in the world:- People who know binary and people who don’t.
Hi, No further comment? Are you even going to look into the matter? So the same as before? A couple of responses then forget it?
Most probably because you didn’t answer all of the questions you have been asked.
Any further comment or is that it?
Aside: TheOne you got a stressful job man 
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I have diligently answered everything I have been asked. Any omission is unintended. The last question was answered with a snapshot (2 actually accidentally) 
of the App requester?
Regards,
Louwin
Can you post a screenshot of your add-on manager?
Is this what you want?
Not sure, is there also one listed in “Extensions”?
Either way you should disable everything with that same and see if that resolves your issue.
I’ve attached snapshots of Extensions and Plugins. I don’t use any services.
I will try to disable everything on Friday (my day off). I WILL try this but don’t expect it to make a difference as it WAS working perfectly with whatever other plugins/extensions/appearance addons I HAD till I added “Theme Font & Size Changer”.
I hadn’t added ANY addons for months(if not years) till I added TF&SC. I immediately noticed the problem with Yahoo then other web pages. Even YOUR page(forum?) has the problem.
Yahoo seems the most affected, about 26 icons have gone missing on my Yahoo Mail page. I could live with the missing icons but the loss functioning of the icons is a different matter. Some icons work but VERY restrictedly. For instance, the “Delete” mail icon works if I click the bottom line of the box.
Also strange is I have updated to Windows 10 from 8.1 and the problem persisted from 8.1 to 10.
Thanks for your response,
louwin
There are 10 kinds of people in the world:- People who know binary and people who don’t.
Why don’t you just disable “Theme Font & Size Changer” and be done with it, then?
Okay. I have disabled everything, everywhere (extensions, Appearance and Plugins). Closed Firefox. Restarted Firefox and the problem persists.
The attachment if the bottom of my current reply (this one!) showing the missing icons.
Sorry, what now!?
Regards,
Louis
There are 10 kinds of people in the world:- People who know binary and people who don’t.
If you want to avoid resetting your whole main profile, then you can try creating a new profile and see if it works there.
If it works there, then we can either carefully sync to that one by one to see what breaks it.
If it doesn’t work there, then you have like an anti-virus or something messing.
To create a new profile: https://addons.mozilla.org/en-US/firefox/addon/profilist/
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