Version:            (using KDE 3.5.8)
Installed from:    Debian testing/unstable Packages
OS:                Linux

In qt 3.* applications (seen in Konqueror and Kate) scrolling the window has the effect that a part of the previous portion of the screen doesn't scroll until I force a refresh clicking the screen or move the window etc.
Sometimes even the icons on the desktop or in Konqueror come out "half rendered"
To reproduce the problem all I have to do is trying some web browsing... really annoying!

Iceweasel, Amule, Ekiga, Gimp and all the gtk apps I use don't suffer this problem, so I guess it's a qt-nvidia-compiz issue...

You have my Kde version, my distro is Debian lenny, the version of my Nvidia driver is 169.09 (but previous versions had the same problem). I suffered this with Compiz from ufficial repos of Debian and Compiz-Fusion from http://download.tuxfamily.org/osrdebian unstable compiz-fusion-git wich I'm actually using.

My xorg.conf is this (there are some commented options I played with, I'm using it as is here and except for the issue all works fine):

Section "ServerLayout"
    Identifier     "Default Layout"
    Screen         "Default Screen" 0 0
    InputDevice    "Generic Keyboard"
    InputDevice    "Configured Mouse"
    InputDevice    "Synaptics Touchpad"
EndSection

Section "Files"
EndSection

Section "Module"
    Load           "glx"
    Load           "dbe"
#    Load           "extmod"
EndSection

Section "InputDevice"
    Identifier     "Generic Keyboard"
    Driver         "kbd"
    Option         "CoreKeyboard"
    Option         "XkbRules" "xorg"
    Option         "XkbModel" "pc105"
    Option         "XkbLayout" "it"
EndSection

Section "InputDevice"
    Identifier     "Configured Mouse"
    Driver         "mouse"
    Option         "CorePointer"
    Option         "Device" "/dev/input/mice"
    Option         "Protocol" "ImPS/2"
    Option         "Emulate3Buttons" "true"
EndSection

Section "InputDevice"
    Identifier     "Synaptics Touchpad"
    Driver         "synaptics"
    Option         "SendCoreEvents" "true"
    Option         "Device" "/dev/psaux"
    Option         "Protocol" "auto-dev"
    Option         "HorizScrollDelta" "0"
EndSection

Section "Monitor"
    Identifier     "Monitor Generico"
    HorizSync       28.0 - 64.0
    VertRefresh     43.0 - 60.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "nVidia Corporation G72M [Quadro NVS 110M/GeForce Go 7300]"
    Driver         "nvidia"
EndSection

Section "Screen"

#    Option         "Overlay" "False"
    Identifier     "Default Screen"
    Device         "nVidia Corporation G72M [Quadro NVS 110M/GeForce Go 7300]"
    Monitor        "Monitor Generico"
    DefaultDepth    24
    Option         "RenderAccel" "True"
    Option         "UseCompositeWrapper" "true"
    Option         "AllowGLXWithComposite" "True"
    Option         "AddARGBGLXVisuals" "True"
    Option         "AddARGBVisuals" "True"
    Option "TripleBuffer" "True" 
#    Option         "DisableGLXRootClipping" "true"
    Option         "NoLogo" "True"
#    Option         "ExactModeTimingsDVI" "True"
    Option         "DamageEvents" "True"
    SubSection     "Display"
        Depth       24
        Modes      "1280x800"
    EndSubSection
EndSection

#Section "Extensions"
#    Option         "Composite" "Enable"
#EndSection