Description of problem:

When I try to view

  http://docs.python.org/library/zipfile.html

with firefox it crashes as I scroll down the page.  It says

QPixmap: Invalid pixmap parameters
The program 'firefox' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadAlloc (insufficient resources for operation)'.
  (Details: serial 52510 error_code 11 request_code 53 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
Locking assertion failure.  Backtrace:
#0 /usr/lib64/libxcb-xlib.so.0 [0x34f3a0097c]
#1 /usr/lib64/libxcb-xlib.so.0(xcb_xlib_lock+0x17) [0x34f3a00af7]
#2 /usr/lib64/libX11.so.6 [0x34f3e4c610]
#3 /usr/lib64/libXrender.so.1(XRenderFreePicture+0x46) [0x34f6204826]
#4 /usr/lib64/libQtGui.so.4 [0x31a96468eb]
#5 /usr/lib64/libQtGui.so.4 [0x31a9647270]
#6 /usr/lib64/libQtGui.so.4(_ZN7QPixmap5derefEv+0x53) [0x31a963cb93]
#7 /usr/lib64/libQtGui.so.4(_ZN7QPixmapD1Ev+0x24) [0x31a963ced4]
#8 /usr/lib64/libQtGui.so.4 [0x31a971ef9b]
#9 /usr/lib64/libQtGui.so.4 [0x31a9717719]
#10 /usr/lib64/libQtGui.so.4 [0x31a9646848]
#11 /usr/lib64/libQtGui.so.4 [0x31a9647270]
#12 /usr/lib64/libQtGui.so.4(_ZN7QPixmap5derefEv+0x53) [0x31a963cb93]
#13 /usr/lib64/libQtGui.so.4(_ZN7QPixmapD2Ev+0x24) [0x31a963cf24]
#14 /usr/lib64/libQtGui.so.4 [0x31a9641d83]
#15 /usr/lib64/libQtGui.so.4 [0x31a964238f]
#16 /usr/lib64/libQtGui.so.4 [0x31a9641a75]
#17 /lib64/libc.so.6(exit+0x9d) [0x36568358ad]
#18 /usr/lib64/libgdk-x11-2.0.so.0 [0x3bf9a64767]
#19 /usr/lib64/libX11.so.6(_XError+0xf4) [0x34f3e45524]

I'm attaching a more detailed output from 'firefox -g -sync ...' and gdb.  Note from the gdb session trace that thread #8 cannot be queried (it generates a gdb internal error).  Oops!

Version-Release number of selected component (if applicable):

libX11-1.1.4-1.fc9.x86_64
qt-x11-4.4.3-5.fc9.x86_64
gtk2-2.12.12-1.fc9.x86_64
libXrender-0.9.4-3.fc9.i386
libxcb-1.1-5.fc9.x86_64
glibc-2.8-8.x86_64
xorg-x11-drv-ati-6.8.0-19.fc9.x86_64

(note that the firefox debug trace indicates references to the fglrx driver, but it is not installed on this system.)

How reproducible:

Always

Steps to Reproduce:
1. start firefox
2. go to http://docs.python.org/library/zipfile.html
3. scroll down with the arrow keys
  
Actual results:


Expected results:


Additional info:

This is using a KDE desktop (should be obvious from the firefox traceback).