Don't want to register, so here is my report:
I use Fedora 7
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:184.108.40.206) Gecko/20080416 Fedora/220.127.116.11-1.fc7 Firefox/18.104.22.168
Problem is only in mid area of page of planet, size bigger if Ctrl++ used to increase text size, scrolling up or down. Horizontal stripes that stay put on the same spot and the rest of the page seems to float under them when you scroll. Number and vertical size of these horizontal stripes depends how you scroll and how fast.
Whats is rendered inside these strips, also depends with what you scroll and how fast. Stripes flicker(up/down slight movement when scrolling with mousewheel or up/down keys and smoothscrolling ON). Cannot take screenshot because when focus is shifted to outside of firefox, like Application Menu, the firefox window redraws the page correctly.
But when I set "Smooth Scrolling" OFF from settings and scroll clicking on vertical scroll bar or using page up/down keys, rendering is OK!!! Mousewheel or up/down keys still show the problem.
Problem started maybe some 2+ weeks ago?
Juha from Kuopio, Finland
Can find my contact email from redhat bug #447452