Some users of the Firefox web browser have reported issues with blurry fonts after updating it to the latest release version Firefox 17.0. The issue seems to only affect users running the Windows operating system that have installed or upgraded to Firefox 17.0. Mozilla filed a bug report shortly after the release of the new Firefox version which in the meantime has been marked as fixed so that upcoming versions of the web browser won't cause the font blurriness for users affected by it.
Research of the problem indicates that the parameter gfx.content.azure.enabled was set to true in Firefox 17.0, while it had been set to false in previous versions of the browser. Jonathan Kew explains the concept behind the parameter:
With azure content enabled, Firefox uses subpixel font rendering throughout chrome and content, regardless of whether ClearType is enabled or disabled in the Windows control panel.
What this means, basically, is that Firefox 17.0 won't respect the system's ClearType setting which in turn causes the font display issues in the browser. In particular, users who have disabled ClearType in Windows may be affected by the issue.
A temporary solution for now is to set the parameter to false again. Let me show you how that is done:
- Enter about:config into the Firefox address bar to load the advanced configuration.
- If this is your first time, you may receive a warning page that you need to click through.
- Type gfx.content.azure.enabled into the search form on the page.
- Double-click the entry or right-click it and select Toggle to change the value to false.
- Restart the web browser.
The font rendering issue should be a thing of the past after the change.
Note that Thunderbird 17.0 is likely affected by the same bug as well. To switch the parameter in the email program do the following:
- Click on Tools > Options.
- Switch to the Advanced > General tab and click on Config Editor near the bottom of that page.
- Type gfx.content.azure.enabled into the search form
- Double-click the preference to set it to false
- Restart Thunderbird.
Mozilla has not mentioned yet when Firefox 17.0.1 will be released, but it is likely that it is going to happen in the near future. (via Sören)