On Mon, Jun 20, 2005 at 03:50:52AM -0500, Richard Rauch wrote:
> I've found that on my AMD64 box, when I press the left and right buttons
> simultaneously, I get a middle-button event.  This mouse has a proper
> middle button, and I have never asked XFree86 explicitly to emulate the
> third button this way.  I cannot see any sign of the feature being enabled
> in /etc/XF86Config, either.
> 
> I have not seen this on other systems, but have not looked very hard for
> it, either.  It is rather annoying and I'd like to turn it off.
> 
> I thought that I'd ask here, first, to see if anyone else can confirm
> this behavior or maybe suggest a way to fix it.  (For all I know, it
> could be a "feature" of the Logitech USB optical mouse that I'm using...but
> posting here seems like a place to start.)

Same here on -current i386 and amd64, with both PS2 and USB mice
... According to the mouse(4) man page, it is off by default.

A quick look to the corresponding code shows that the X server has
some `soft emulation' turned on if "Emulate3Buttons" option is not set
in configuration file. If i remember correctly, this emulation must
stop as soon as the middle button is pressed ... Currently it does
not and looks like a bug to me.

Just add `Option "Emulate3Buttons" "false"' in your config file for
now ;-)

-- 
Nicolas Joly

Biological Software and Databanks.
Institut Pasteur, Paris.