Dual head + 1 monitor

[David Courtney]

If you're not a multiple monitor person, you can ignore this thread.

For the past 2+ years, I've been enjoying OpenBox's wonderful handling
of dual-head display.  My primary video card is (currently) as
follows:

01:00.0 VGA compatible controller: nVidia Corporation NV43 [GeForce
6600/GeForce 6600 GT] (rev a2)

It has dual DVI output which drive two of my Hitachi CML174SX LCD displays.

With my xorg.conf file configured for TwinView (using the proprietary
nvidia drivers) I've had flawless dual head video display.

If I maximize a window on the left monitor, it expands to fill only
the left monitor.  If I drag a window to the edge of the right
monitor, it knows to "resist" at the edge of the left/right monitor.
(Not so be a suck up, but OpenBox handles dual displays better than
any other WM I've used.  And I've tried *many* other WM's.)

So.  No problem so far....

Today I added a PCI video card to my machine, as follows:

00:13.0 VGA compatible controller: nVidia Corporation NV34 [GeForce FX
5200] (rev a1)

I intended it to drive my 3rd Hitachi CML174SX LCD display.

I updated my xorg.conf as follows (relevant sections only):

Section "ServerLayout"
    Identifier     "Default Layout"
    Screen         0 "Default Screen"
    Screen         1 "Left Wing" LeftOf "Default Screen"
    InputDevice    "Generic Keyboard"
    InputDevice    "Configured Mouse"
EndSection

Section "Monitor"
    Identifier     "CML174SX"
    HorizSync       24.0 - 80.0
    VertRefresh     56.0 - 75.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Generic Video Card"
    Driver         "nvidia"
    BusID          "01:00:0"
EndSection

Section "Device"
	Identifier	"NVidia GeForce 5200FX"
	Driver		"nvidia"
	BusID		"00:19:0"
EndSection

Section "Screen"
    Identifier     "Default Screen"
    Device         "Generic Video Card"
    Monitor        "CML174SX"
    DefaultDepth    24
    Option         "NoLogo" "1"
    Option         "TwinView"
    Option         "TwinViewOrientation" "RightOf"
    Option         "MetaModes" "1280x1024,1280x1024"
    SubSection     "Display"
        Depth       24
        Modes      "1280x1024" "1024x768" "800x600" "640x480"
    EndSubSection
EndSection

Section "Screen"
	Identifier	"Left Wing"
	Device		"NVidia GeForce 5200FX"
	Monitor		"CML174SX"
	DefaultDepth	24
	Option		"NoLogo" "1"
	SubSection	"Display"
		Depth	24
		Modes	"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
EndSection


As was before, when I enter the X Window System, my primary two panels
(driven my the AGP card) are seen as 1 wide display.  (Which is what I
want.)

The far left panel ("Left Wing") is driven my the PCI card and is
independent of the primary panels.  (Which is, also, what I want.)

The problem I'm now experiencing (finally getting to the point) is
that windows on my primary 2 panels no longer behave properly.  By
"properly", I mean when I maximize a window on either display, it now
fills the screen on both displays.  When I move a window the edge of
one screen, there is no resistance at the border.  It's as if the two
primary panels now "think" that they are physically 1 screen.

The "Left Wing" panel is behaving properly.  I have a 2nd instance of
OpenBox running on that display (:0.1).  When I maximize a window, it
only fills that screen.  When I move a window near any edge, it
resists as it should.

So my question is about the primary two panels.  Why are they now
acting as though they have become 1 physical screen with no edge
resistance between them?  Has anyone experienced this?  Is my
configuration obviously wrong?