Copy & paste into/from X apps no longer works

Ok, confirmed -rootless mode is breaking this. Now to figure out if pasted needs to do something different or if -rootless mode is broken in Xmir.

After some more investigation, in the non-rootless mode, Xmir sets the _MIR_WM_PERSISTENT_ID atom on the root window, and since pasted just queries the default root window, this works fine.

However, in rootless move, one of the children on the "root" window gets the _MIR_WM_PERSISTENT_ID atom, thus pasted is not able to get the persistent surface id.

So, we can approach this one of two ways.

1. Xmir can set _MIR_WM_PERSISTENT_ID on the root window regardless of the mode.
2. pasted will have to get smarter and try to first query the root window and if that returns nothing, then do an XQueryTree() and iterate over child windows until the _MIR_WM_PERSISTENT_ID is found.

I prefer 1 since it will offer consistency, bit I'm not sure if there are any pitfalls with that approach. Will subscribe xmir to this bug and get duflu's advice:)

I don't doing it in xmir is the right place now, especially for rootless, because a new window that is opened from the app will get it's own unique persistent surface id. pasted will definitely need to be modified to account for the rootless scenario.

Removing the xmir task...

Fix committed into lp:libertine at revision 444, scheduled for release in libertine, milestone Unknown

This bug was fixed in the package libertine - 1.7.1+17.04.20170331-0ubuntu1

---------------
libertine (1.7.1+17.04.20170331-0ubuntu1) zesty; urgency=medium

  [ Chris Townsend ]
  * When starting pasted, ensure DISPLAY is set and valid before continuing to
    run. (LP: #1666472)
  * Fix pasted to work with rootless Xmir. (LP: #1671257)
  * Add a '-x' option to pkill so it only kills the libertined process(es)
    and nothing else. (LP: #1676005)
  * Remove hard-coded dependency on libraries.

  [ Larry Price ]
  * Bump version to 1.7.1
  * Gracefully handle creating a LibertineContainer object when the container
    backend is unavailable.
  * Update libertine xmir components to not depend on container backends.
    (LP: #1671938)
  * Catch all errors and gracefully shutdown libertined. (LP: #1671009)
  * Fix method call from ContainerControl d-bus to interfaces.
  * Update signal handlers in test_libertine_service to reflect new API.
  * Inject client for accessing ContainerControl within containers.
  * Rearchitect libertine service python backend for simpler access to running
    tasks. (LP: #1669091)
  * Ignore completions from dependencies during snapcraft build.
  * LXD needs to forward host environment to container when running arbitrary
    commands.
  * Add client object to list_app_ids_task to avoid making reentrant service
    calls.
  * Take advantage of new network subcommand during lxd init on newer
    installs.
  * Prevent installing empty package names and appropriately update status for
    unstopped containers.
  * Modifications to make test_libertine_service more stable.
  * Reopen the database file after every failure to grab the lock.
    (LP: #1662655)

 -- Larry Price <email address hidden> Fri, 31 Mar 2017 20:09:39 +0000