big white blinking box when fonts packages are installed

[Chuck Anderson]

I've noticed recently that when doing yum update that includes font 
packages, I see a big white box flash on the screen then disappear.  
Perhaps it is my root window/background changing to white, I'm not 
sure.  It happens too quickly for me to tell what it is or what is 
causing it.

I just noticed this when installing a single package with rpm 
directly:

java-1.6.0-sun-fonts-1.6.0.11-1jpp.i586.rpm

I tried running each part of the %post scriptlet in that package but 
it doesn't happen when running these manually:

postinstall scriptlet (using /bin/sh):
{
    # Legacy font handling

    /usr/bin/ttmkfdir -d /usr/share/fonts/java -o /usr/share/fonts/java/fonts.scale

    # Mandrake workaround
    /usr/bin/perl -pi -e 's at 0-c-0@0-p-0 at g' /usr/share/fonts/java/fonts.scale

    /usr/X11R6/bin/mkfontdir -e /usr/X11R6/lib/X11/fonts/encodings -e /usr/X11R6/lib/X11/fonts/encodings/large /usr/share/fonts/java

    /usr/sbin/chkfontpath -q -a /usr/share/fonts/java

    # The following commands will be executed on upgrade by their respective
    # packages

    # Late legacy font handling
    if [ -x /usr/bin/redhat-update-gnome-font-install ] ; then
        /usr/bin/redhat-update-gnome-font-install
    fi

    if [ -x /usr/bin/redhat-update-gnome-font-install2 ] ; then
        /usr/bin/redhat-update-gnome-font-install2
    fi

    # Modern font handling
    if [ -x /usr/bin/fc-cache ] ; then
        /usr/bin/fc-cache -f /usr/share/fonts
    fi
} || :

Maybe its a trigger script?  How would I find out?