How to stop upgrade message for firefox and safari?

[artms]

I don't use either one but this comes up everytime I try to access my mail acount from my yahoo. There is no option to not get this message. How do I stop it? I clicked continue without upgrade but that doesn't stop it.
This happened when I upgraded Chromium. I am getting upgrade messages for Safari and
Firefox while I'm using Chromium on Ubuntu and I do not have Firefox or Safari.
This is what I get
Yahoo recommends you upgrade your browser to enjoy all the features in the new Yahoo Mail
Firefox
Optimized for Yahoo

Upgrade
Safari
Latest Version

Upgrade
Continue without upgrading.
Please check our help pages for any questions or support.

[Masterlamp462]

According to Yahoo staff, this may be due to a web browser issue. You may want to consider upgrading your current web browser, switching to a different web browser or you can follow the advice in this Yahoo Help page:

Fix browser and feature problems on Yahoo -- http://help.yahoo.com/kb/index?page=cont...=PROD_ACCT

To download a new web browser or update your current browser:

Web browsers supported by Yahoo -- http://help.yahoo.com/kb/index?page=cont...=PROD_ACCT

Another user offered this solution: Right click on 'Continue without upgrading', select 'Open Link in New Tab' or 'Open Link in New Window'.