XWin ignores all parameters related to multiple monitors

[Jon TURNEY]

On 04/05/2014 06:56, Lukas Haase wrote:
> I use Cygwin/X to display a CAD application on my Windows cient. For
> some reason new windows always open on the secondary display and I
> always need to manually drag them to my primary display. That's sooo
> annoying (since UNIX applications tend to open new windows on every action).

I'm assuming that your secondary display is to the left of your primary 
display.

I think that it's a bug that these windows are appearing at the 
top-left, rather than on the primary display, in that we don't 
distinguish well enough between "the application asked us to place the 
window at 0x0" and "the application didn't specify where to put the window"

It would help if you could give the name of this application, and can 
you install 'xprop', and show the output you get from running that, then 
clicking on one of the window which gets placed incorrectly.

> To avoid this, I want to disable the second monitor (and *only* use the
> primary). But whatever I do, XWin seems to ignore whatever I supply. For
> example, I start
>
> /usr/bin/startxwin.exe -- -nomultiplemonitors
> /usr/bin/startxwin.exe -- -screen 0 @1 -nomultiplemonitors
> /usr/bin/startxwin.exe -- -screen 0 @1
> /usr/bin/startxwin.exe -- -mwextwm -screen 0 @1 -nomultiplemonitors
>
> and so on.
> Nothing works - everything as before. When I select "Hide Root Window"
> from the tray icon I see that the root window indeed covers both monitors.

This is not how it behaves for me.  Using -nomultiplemontiors, or an 
explicit -screen setting shows an appropriately sized root window when 
turning off "Hide Root Window". (Although this is not terribly useful as 
you can move the Windows windows out of this area, which causes their 
contents to not be drawn)

Can you check if the screen dimensions reported by xdpyinfo match those 
you are requesting, and attach your /var/log/xwin/XWin.0.log?

Separately, it's possible that we should do something better with the 
combination of -nomultiplemontors and -multiwindow, but it's not quite 
clear to me what.  (See discussion [1])

[1] https://sourceware.org/ml/cygwin-xfree/2011-07/msg00007.html

-- 
Jon TURNEY
Volunteer Cygwin/X X Server maintainer

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