Can you include a screenshot of the problem?

• How do I create a screenshot of my problem?

Is a newer driver available for your graphics card?

• Upgrade your graphics drivers to use hardware acceleration and WebGL

Does the problem go away if you do the following?

1. Type about:config into the address bar and press Enter.
2. Press the big button to bypass the warning.
3. In the lower pane, right-click anywhere and choose New, then Boolean.
4. Name the preference layout.paint_rects_separately and set its value to true.
5. Restart Firefox. If the problem doesn't go away, right-click the preference you created earlier and choose Reset; it will disappear when Firefox is restarted next.

I have a screen shot of the issue at hand and included with this reply. I don't think graphics drivers are an issue here because I'm not having any problems with scrolling other graphic displays. It is only happening in Firefox and Thunderbird e-mail client.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

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

Note that you seem to be missing a font for the Bengali script.

• http://en.wikipedia.org/wiki/Bengali_script