It came to me in a week or so that certain pages (Facebook, StrackOverflow, some news sites) have text rendering errors in Firefox. As a workaround if I refresh the page, or simply select and deselect the buggy text, the unpleasant effect disappears.

I don't have this effect in Internet Explorer or in any of my desktop applications.

• Windows 7 Pro 64bit (fresh)
• Firefox 19.0.2 (fresh)
• Ati Radeon HD 4600 Series (fresh drivers)

Thanks for the help in advance!

Update 1/2

I have only three addons: Forecastfox, Hungarian spell checking dictionary and Quick locale switcher. The latter two are installed after the effect appeared. I disabled the first individually and did not helped.

But if I start my firefox with disabled addons I cannot reproduce the error. As far as I know this mode does not mean disabled plugins, which I do have (Adobe Acrobat, Citrix ICA Client, Google Earth plugin, Google update, Java Deployment Toolkit 6, MS Office 2010, MS Windows Media Player Firefox, Shockwave Flash, Silverlight, VLC Web).

Update 2/2

If I disable all plugins and extensions I still have the problem. If I start Firefox with disabled addons then I cannot reproduce the problem.