Having the same issue in Firefox and Thunderbird with ATI FGLRX driver 10.8 on Kubuntu 10.04.1. It appears to be related to ATI drivers after I upgraded from 10.7 to 10.8 of the proprietary ATI driver, however the issue is not seen in KDE, nor the Konqueror and Ephipany browsers. Just Firefox and Thunderbird.
Having the same issue in Firefox and Thunderbird with ATI FGLRX driver 10.8 on Kubuntu 10.04.1. It appears to be related to ATI drivers after I upgraded from 10.7 to 10.8 of the proprietary ATI driver, however the issue is not seen in KDE, nor the Konqueror and Ephipany browsers. Just Firefox and Thunderbird.