The machine in question is running Arch Linux on x86_64 and using their official, most up-to-date packages.

I access this machine remotely by running a KDE 4.7 session inside Xephyr on another machine via X forwarding.

Everything works great for a while, but when left idle for some time (say 10 minutes,) the Kickoff launcher menu opens correctly and all task manager icons highlight on hover, but actually clicking on an application icon in either of these locations (like Konsole or Chromium) has absolutely no effect, the applications don't run. I have to kill my session and start a new one to be able to open applications again.

Does anyone have any thoughts as to why this might be happening?

Are any debugging error messages left in ~/.xsession-errors on the machine where your session is actually being executed? (Or the equivalent log files...)

Here's how I start a remote session on a "client" machine:

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#!/bin/bash
Xephyr -ac -screen 2000x1125 -br -host-cursor &> ~/xephyr_log.txt :1 &
export DISPLAY=:1
ssh -Xf user@myhost 'bash -l -c "dbus-launch /usr/bin/startkde"' &> ~/ssh_log.txt


An explanation of the above:

1) Xephyr is started locally and assigned to display 1.

2) DISPLAY environment variable is forced to 1.

3) Start the remote KDE session. startkde is wrapped by dbus-launch, which is wrapped by bash. The bash wrapping is there so that /etc/profile is properly sourced into the running KDE environment (so that Java is on the PATH, etc.)

When clicking on something like the Konsole icon and not having Konsole open, the following appears in ssh_log.txt:

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konsole: cannot connect to X server localhost:10.0
unnamed app(5743): Communication problem with  "konsole" , it probably crashed.
Error message was:  "org.freedesktop.DBus.Error.NoReply" : " "Message did not receive a reply (timeout by message bus)" "


...and then later:

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ProcessControl: Application '/usr/bin/akonadi_agent_launcher' stopped unexpected (Process crashed)
Application '/usr/bin/akonadi_agent_launcher' crashed! 1 restarts left.
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' stopped unexpected (Process crashed)
Application '/usr/bin/akonadi_agent_launcher' crashed! 1 restarts left.
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' stopped unexpected (Process crashed)
Application '/usr/bin/akonadi_agent_launcher' crashed! 1 restarts left.
akonadi_agent_launcher: cannot connect to X server localhost:10.0
akonadi_agent_launcher: cannot connect to X server localhost:10.0
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
akonadi_agent_launcher: cannot connect to X server localhost:10.0
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
akonadi_agent_launcher: cannot connect to X server localhost:10.0
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
akonadi_agent_launcher: cannot connect to X server localhost:10.0
akonadi_agent_launcher: cannot connect to X server localhost:10.0
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
akonadi_agent_launcher: cannot connect to X server localhost:10.0
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
"/usr/bin/akonadi_agent_launcher" crashed too often and will not be restarted!
akonadi_agent_launcher: cannot connect to X server localhost:10.0
akonadi_agent_launcher: cannot connect to X server localhost:10.0
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
"/usr/bin/akonadi_agent_launcher" crashed too often and will not be restarted!
ProcessControl: Application '/usr/bin/akonadi_agent_launcher' returned with exit code 1 (Unknown error)
"/usr/bin/akonadi_agent_launcher" crashed too often and will not be restarted!


So it seems like after some time of being left idle, DISPLAY is reset back to 0 instead of 1, so the new windows don't attach inside my existing Xephyr->KDE session. I have no idea why that's happening. Thoughts?

I would suggest checking that the variable is not being reset somehow by the startkde scripts.

I figured out that this probably isn't related to the DISPLAY variable, but now I have absolutely no idea what it could be.

Right after the session loads up, Konsole shows that the value of DISPLAY is localhost:10.0. This is the same display that shows up in the logs where applications fail to open up (after the session has been left idle for a few minutes.)

If the startkde scripts were to blame, wouldn't nothing launch as soon as KDE loads up? Why would this only start happening only after a few minutes of the session being idle?