hello RalphB, you can attach a screenshot in a reply to your original post...

Reset the page zoom on pages that cause problems.

• View > Zoom > Reset (Ctrl+0 (zero); Command+0 on Mac)

• http://kb.mozillazine.org/Zoom_text_of_web_pages

Try to disable hardware acceleration in Firefox (you need to close and restart Firefox).

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Many thanks. This seems to have eliminated the problem.

Many thanks. The problem now seems to have gone away.

This was the problem. Hopefully, now gone ! Thank you for your help.

I have the same problem. I have changed the zoom and disabled acceleration and it works on the Mozilla site. However, it doesn't work for most other websites..web mail, Facebook, etc. A strange thing I've noticed is that if I highlight text the problem goes away but only for the text I've highlighted. I have Firefox 27. Any other ideas???

Hello tnsquirejay, The problem you have seems to be exactly as the one I was experiencing (highlighting etc). However, I do not have (or use) the other features which you mention and therefore I am unable to comment regarding this. I do hope that someone may have the solution for you. Needless to say, I will keep an eye on the forum.

Note that Firefox stores the zoom settings per domain, so you may have to reset the page zoom on those pages as well.

Try to disable Direct2D by setting the gfx.direct2d.disabled pref to true on the about:config page and leave hardware acceleration otherwise enabled.

See also comment 414 in bug 812695:

• https://bugzilla.mozilla.org/show_bug.cgi?id=812695#c414

You can try to uninstall Windows update KB2670838 if you have this update.

• http://support.microsoft.com/kb/2670838

Where do I change that setting? I can't find it.

Is this about the page zoom or about the pref that is mentioned in comment 414 of the bug report?

The layout.paint_rects_separately pref doesn't exist by default and need to be created on the about:config page via the right-click context menu.

• http://kb.mozillazine.org/about:config

--- Use this to reset the page zoom for the page in the currently selected tab:

• View > Zoom > Reset (Ctrl+0 (zero); Command+0 on Mac)

• http://kb.mozillazine.org/Zoom_text_of_web_pages
• http://kb.mozillazine.org/browser.zoom.siteSpecific
• http://kb.mozillazine.org/browser.zoom.full

I also have this problem after update to Firefox 28. is it bug from Firefox? My website that using Open Sans look blurry. What I must to do with the css? because not everyone know how to set about:config :(

please help

SOLVED (weird but solved)

I had the same problem on both my PCs (one with Windows 7, the other with Windows XP). I tried the above fixes without success:

• zoom = zero
• gfx.direct2d.disabled = true
• hardware acceleration = disabled

I read that Open Sans displayed correctly in Firefox 17.0 so I downloaded the portable version as I wanted to post two snapshots of the issue (one with FF 17.0 and one with FF 29.0) hoping to find some help. (I did this on my Win7 PC)

I launched FF 17.0, went to a page that used Opens Sans and noticed that FF 17.0 actually displayed the font correctly. I took the snapshot and closed FF 17.0. I then opened the same link in FF 29.0 to get the second snapshot and... magically Open Sans displayed correctly in FF 29.0 too! (I restarted FF 29.0 and it's still working).

Present configuration is:

• gfx.direct2d.disabled = false
• hardware acceleration = enabled

After lauching (and then closing) FF 17.0 portable the issue in FF 29.0 had gone.

Absolutely don't know why. Experts may help us understand.