Windows 7 or newer users who run Firefox may have noticed text rendering issues in the web browser for some time now.
The first bug addressing the issue was filed on Bugzilla more than a year ago, to be precise, on November 16, 2012.
Other users added their experience which all came down to recent updates of Windows 7 and Windows 8 that seemed to cause the issue.
Examples of how text looked like on affected systems were posted as attachments. Situations were this was experienced included while browsing Google Maps and Google News, while using drop down menus, after using Ctrl, or after scrolling.
Surprisingly though, it could be narrowed down a bit further, as AMD graphics cards seemed to be affected by it almost exclusively.
It was also clear that this was not really a issue of how Firefox handled text in the browser, but that it was caused by third-parties that Mozilla had no control over.
Firefox 26 was released on December 10, 2013, and with it came a workaround solution for affected users. Mozilla did mention it in the official release notes, but it was somewhat hidden in there, and it only linked to the bug listing and not a post explaining the workaround in detail (this has now been updated so that users are taken directly to the comment that details the workaround).
What makes this fix special is that it needs to be enabled before the issue is fixed. There is however no configuration switch to do so, which means that affected Firefox users need to use the about:config dialog to do so.
- Type about:config in Firefox's address bar and tap on the Enter-key on the keyboard.
- Confirm you will be careful.
- The preference does not exist by default, which means that you will have to create it.
- Right-click in the content area and select New > Boolean from the context menu.
- Name it layout.paint_rects_separately.
- You are asked whether you want it to have a true or false value. Select True as it enables the feature.
- Restart Firefox so that the changes can take effect.
Note: Performance may be lower when set to true. It is suggested that you only create the preference if you experience text rendering bugs in Firefox.
You can disable the fix at any time by setting the value of the parameter to False.
The bug itself is still open, and it is likely that the performance issues that go along with it will be fixed in future releases. It is not clear yet if the fix will be implemented automatically in future versions so that Firefox users do not need to create the parameter manually on their systems.
If you are experiencing text rendering bugs in Firefox, try this fix and let me know if it resolved them for you (via Sören).