Try resetting Firefox setting to factory settings (default settings) and if it persists, please contact us again!

You can try to disable hardware acceleration in Firefox.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

You need to close and restart Firefox after toggling this setting.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can check if there is an update for your graphics display driver and check for hardware acceleration related issues.

• https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

If you notice problems just on particular websites, could you give a link to a site or two and point out the area with the problem, or post a screen shot showing the problem?

If you have recently installed any new fonts in the Helvetica family, please also see this thread: Problem with fonts. If I enable Hardware acceleration bold fonts look weird, but if I disable it, bold fonts look good, but normal fonts look weird.

Try to set layout.css.devPixelsPerPx to 1.0 (default is -1) on the about:config page. If necessary adjust its value in 0.1 or 0.05 steps (1.1 or 0.9) until icons or text looks right.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

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

You can look at the Default FullZoom Level or NoSquint extension to set a default font size and page zoom on web pages.

• Default FullZoom Level: https://addons.mozilla.org/firefox/addon/default-fullzoom-level/
• NoSquint: https://addons.mozilla.org/firefox/addon/nosquint/