Mouse problems with ALT+TAB on SDL OpenGL non-fullscreen game

[Nerius Landys]

Howdy.  I am running a video game that is a derivative of quake3.  The exact
game is called Urban Terror.  I'm compiling this game against SDL.  This
enables me to use ALT+TAB to switch between the game and other desktop
apps.  I have tried compiling from the ports version (games/iourbanterror)
and the plain vanilla non-ports version, and I am getting a problem in both
cases.

When I run the game in non-fullscreen mode and after I use ALT+TAB to switch
to another app and then back to the game, the mouse starts acting funny.
It's as if the mouse all of a sudden is limited by some imaginary
rectangular region.  The expected behavior is that if I move the mouse to
the left side, for example, the player will rotate to the left
continuously.  The behavior that I am getting is that once the mouse is
moved to the left (or right) by a certain amount, any further movement in
that direction has no effect.  Like I'm hitting a wall or something.

This problem does not happen if I run the game in fullscreen mode.  It's
only on non-fullscreen (windowed) mode, and only after I ALT+TAB away from
and back to the game.  Any ideas what might be causing this?  Can it be
related to moused?  Here is my xorg.conf:

Section "ServerLayout"
        Identifier     "X.org Configured"
        Screen      0  "Screen0" 0 0
        InputDevice    "Mouse0" "CorePointer"
        InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
        RgbPath      "/usr/local/share/X11/rgb"
        ModulePath   "/usr/local/lib/xorg/modules"
        FontPath     "/usr/local/lib/X11/fonts/misc/"
        FontPath     "/usr/local/lib/X11/fonts/TTF/"
        FontPath     "/usr/local/lib/X11/fonts/OTF"
        FontPath     "/usr/local/lib/X11/fonts/Type1/"
        FontPath     "/usr/local/lib/X11/fonts/100dpi/"
        FontPath     "/usr/local/lib/X11/fonts/75dpi/"
EndSection

Section "Module"
        Load  "extmod"
        Load  "record"
        Load  "dbe"
        Load  "glx"
        #Load  "GLcore"
        Load  "xtrap"
        #Load  "dri"
        Load  "freetype"
        Load  "type1"
EndSection

Section "InputDevice"
        Identifier  "Keyboard0"
        Driver      "kbd"
EndSection

Section "InputDevice"
        Identifier  "Mouse0"
        Driver      "mouse"
        Option      "Protocol" "auto"
        Option      "Device" "/dev/sysmouse"
        Option      "ZAxisMapping" "4 5 6 7"
EndSection

Section "Monitor"
        #DisplaySize      470   300     # mm
        Identifier   "Monitor0"
        VendorName   "SAM"
        ModelName    "SyncMaster"
 ### Comment all HorizSync and VertRefresh values to use DDC:
        #HorizSync    30.0 - 81.0
        #VertRefresh  56.0 - 75.0
        Option      "DPMS"
EndSection
Section "Device"
        Identifier  "Card0"
        Driver      "nvidia"
        VendorName  "nVidia Corporation"
        BoardName   "NV35GL [Quadro FX 3000]"
        BusID       "PCI:1:0:0"
        Option      "NoLogo" "true"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Card0"
        Monitor    "Monitor0"
        SubSection "Display"
                Viewport   0 0
                Depth     1
        EndSubSection
        SubSection "Display"
                Viewport   0 0
                Depth     4
        EndSubSection
        SubSection "Display"
                Viewport   0 0
                Depth     8
        EndSubSection
        SubSection "Display"
                Viewport   0 0
                Depth     15
        EndSubSection
        SubSection "Display"
                Viewport   0 0
                Depth     16
        EndSubSection
        SubSection "Display"
                Viewport   0 0
                Depth     24
        EndSubSection
EndSection