I would like to report a strange behavior of nedit in Debian squeeze amd64.

Some information on my system: I just got a new Lenovo ThinkPad T510 on
which I installed Debian squeeze amd64 (as network driver e1000e of lenny
as provided with netinst did not work, a known issue with this ThinkPad).

I use the standard kernel that comes with squeeze,

Linux mupfel 2.6.32-5-amd64 #1 SMP Sat Oct 30 14:18:21 UTC 2010 x86_64 GNU/Linux

and the standard libc (2.11.2-7, as it comes with squeeze).

In the BIOS, I selected the Intel Integrated Graphics controller

00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02)

and I run xserver-xorg-video-intel (2:2.12.0, as it comes with squeeze) at
1920x1080 (the kernel module is i915).  I use /etc/X11/xorg.conf (a bit
old-fashioned, I know, but I migrated that from my previous ThinkPad), I
guess that the relevant part is

Section "Device"
    Identifier  "Intel Integrated Graphics"
    Driver      "intel"
    Option      "VideoOverlay"      "off"
    Option      "OpenGLOverlay"     "on"
    BusID "PCI:0:2:0"
EndSection

Section "Monitor"
    Identifier  "Generic Monitor"
    Option      "DPMS"          "true"
EndSection

Section "Screen"
    Identifier  "1920x1080"
    Device      "Intel Integrated Graphics"
    Monitor     "Generic Monitor"
    DefaultDepth    24
    SubSection "Display"
        Viewport    0 0
        Depth       24
        Modes       "1920x1080"
    EndSubSection
EndSection

I use fvwm1 (1.24r-55, as it comes with squeeze) as window manager (again,
quite old-fashioned, I know, but I am very happy with this simple window
manager).

My bug report is on nedit (1:5.6~cvs20081, as it comes with squeeze), and
the bug is fully reproducible doing the following: I start nedit that so it
opens an empty window.  Using the menu `File > New' I open a second nedit
window. Now, I move one nedit window over the other nedit window using the
mouse, and lines appear in the upper nedit window (one pixel thick), first
at the location of the inner border of the lower nedit window (left, bottom,
and right) but then move with the moving upper window.  The lines remain in
the upper window until it gets explicitly redrawn.  I can also get these
lines in windows of several other programs (for instance xterm) when I move
these windows over a lower-lying nedit window.  Windows of most other
programs (for instance iceweasel) do not get these lines, which is probably
due to their different window refreshing strategy.  It seems that something
goes wrong in clipping the (re)drawing of the nedit window to the correct
area. From the grey color of the lines I guess that the problem is not the
inner part of the window (which is white in my case) but the frame around it
(which is indeed grey in my case).

I have tried the same with a couple of other programs to exclude that it is
a bug related to X and not to nedit, but I managed to observe the described
effect only when an nedit window is the lower window, so I guessed that it
is related to nedit.

I am somewhat unsure what further information might be helpful to trace this
issue (for instance a screen snapshot), but I will be glad to provide any
information needed.

Many thanks, and best regards,
Markus Porto

Some additional information concerning bug #603161:

I tried a couple of more programs (ones which I normally do not use), and I
found that there are several other programs besides nedit that have the same
problem, for instance xpaint (2.9.1.4-1), xfig (1:3.2.5.b-1+b1) and xmgrace
(1:5.1.22-8), and the problem occurs (mainly) at the sliders at the left and
the bottom of the window. I guess that the programs which are affected use
the same library for drawing window content.

My apologies for having assigned the problem to nedit.

Many thanks, and best regards,
Markus Porto

Than it is probably caused by lesstif. Assuming all these programs
depend on it. If you don't look yourself, I will look into the
dependency, but unfortunately, lesstif bugs are hard to get fixed
because interest of programmers is low (and the code is difficult).

Paul

Many thanks for the quick response.

With squeeze comes lesstif2 (1:0.95.2-1), which provides libMrm.so.2.0.1
and libXm.so.2.0.1. I checked with ldd, nedit binds to libXm.so but not
to libMrm.so. However, neither xpaint not xfig bind to libXm.so (nor to
libMrm.so), so lesstif2 seems not to cause the problem.

I found meanwhile that xpdf shows the same problem. I checked with ldd what
libraries nedit, xpaint, xfig, xmgrace, and xpdf have in common, they are

ld-linux-x86-64.so.2
libc.so.6
libdl.so.2
libICE.so.6
libm.so.6
libSM.so.6
libuuid.so.1
libX11.so.6
libXau.so.6
libxcb.so.1
libXdmcp.so.6
libXext.so.6
libXt.so.6
libz.so.1
linux-vdso.so.1

Some of them can savely be excluded, such as libc.so. Is it possible that
the toolkit library libXt.so causes the problem? How can I check that?

Many thanks, and best regards,
Markus Porto

As far as I can tell everything is possible. I would not know how to
check this, except by somebody that knows enough of the code (but which
one).

Paul

Also gimp (2.6.10-1, as it comes with squeeze) shows the very same problem,
however gimp does not bind libXt. In fact, there is no library that nedit,
xpaint, xfig, xmgrace, xpdf, and gimp have in common (according to ldd).

It seems unlikely that it is only me experiencing this problem. I tried to
figure out whether this problem has already been reported, but I could not
find such bug report. The issue is not particular severe (nothing crashes)
but should not be difficult to fix either. Should I file the bug for other
packages such as xserver-xorg-core or xserver-xorg-video-intel? Or drop an
email to the debian-x@lists.debian.org?

Many thanks, and best regards,
Markus Porto

I do not know what happend, but I cannot reproduce the problem with gimp
anymore. Probably I stared too long on my screen searching for lines...
But I can reproduce the problem with nedit, xpaint, xfig, xmgrace, and xpdf,
So, I think that libXt is again the most likely candicate. The maintainer
of the package libxt6 is, however, also debian-x@lists.debian.org. Should
I drop an email to them?

Many thanks, and best regards,
Markus Porto

reassign 603161 libxt
retitle 603161 Some program windows clip faulty in Squeeze (with fvvmw)
thanks

I reassigned this bug to libXt so they can have a look at it (and if
needed assign the proper package?) They should get this mail automatically.

Paul

Many thanks. Also gv (1:3.7.1-1, as it comes with squeeze) displays the same
problem, and also binds libXt.so.

I checked that fvwm1 is not involved by starting X without window manager,
and the windows still clip faulty.

I do not know what further information might be helpful to trace this issue
in case of a library, but I will be glad to provide any information needed.

Many thanks, and best regards,
Markus Porto

problem persists.

Many thanks, and best regards,
Markus Porto