[unity8] A ghost (shadow only) window opens with some app windows/menus

[dinamic]

ubuntu 17.04 unity8

- install tiled, apt install tiled
- Add "X-Ubuntu-XMir-Enable=false" to /usr/share/applications/tiled.desktop so that it doesn't get launched inside an xmir wrapper
- launch tiled

you'll see a transparent window opened beneath the main window called "Object Types Editor"

see attached screenshot

[dinamic (dinamic6661)]

Loading module: 'libubuntu_application_api_desktop_mirclient.so.3.0.0'
QMetaMethod::invoke: Unable to handle unregistered datatype 'QPlatformWindow*'
QMetaMethod::invoke: Unable to handle unregistered datatype 'QPlatformWindow*'
QMetaMethod::invoke: Unable to handle unregistered datatype 'QPlatformWindow*'
qt.qpa.mirclient: Attempted to deliver an event to a non-existent window, ignoring.
qt.qpa.mirclient: Attempted to deliver an event to a non-existent window, ignoring.

[Lukáš Tinkl (lukas-kde)]

That warning is fixed by https://code.launchpad.net/~aacid/qtubuntu/fix_unregistered_metatype_warning/+merge/317633

No idea if it also fixes the reported bug though

[dinamic (dinamic6661)]

thanks :D nope, it's still the same with silo 2481

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

Confirmed, but I think I've been seeing this in GTK apps. Can't remember where.

[kevin gunn (kgunn72)]

understanding is that this will be fixed by this commit
https://code.launchpad.net/~xmir-team/xorg-server/+git/xmir/+ref/xmir-1.18
just needs to make it's way into archive

[kevin gunn (kgunn72)]

sorry, commit was this one
https://git.launchpad.net/~xmir-team/xorg-server/+git/xmir/commit/?id=8a53ab14880167946e805d3c16bab167fbb03683

[Daniel van Vugt (vanvugt)]

Interesting thought that this might be Xmir's (or any toolkit's) fault. Although doesn't comment #1 show a native (GTK/Qt) app without Xmir?

dinamic: Can you check if Xmir is running when the bug occurs?

I'm also not aware of the bug ever occurring in Mir demo servers, so that's more evidence this is not Xmir's fault.

[dinamic (dinamic6661)]

@daniel, tiled is running native, i don't see any Xmir process

[Daniel van Vugt (vanvugt)]

Oh, I just saw the same bug in nautilus + mir_proving_server when opening a menu. Seems like this might be a general Mir/toolkit bug.

[Daniel van Vugt (vanvugt)]

Confirmed, but it doesn't seem to happen every time.

'tilded' appears to be a native Qt app, although I'm not sure if that's relevant. When I ran it under mir_proving_server there was no ghost window problem. So this makes me think either Unity8 is displaying windows whose state is 'hidden', or we have a general window management/scene bug (because similarly after closing some dialogs they stay visible).

[Daniel van Vugt (vanvugt)]

I mean 'tiled'

[Daniel van Vugt (vanvugt)]

If you select View > Object Types Editor then the ghost window becomes active. So this makes me think it just exists from the beginning and was meant to be hidden.

[Alan Griffiths (alan-griffiths)]

Testing with miral-app I don't see this hidden window until it becomes visible.

[Alan Griffiths (alan-griffiths)]

Oh, and tiled is a Qt application, so I think gtk3+ is innocent

[Daniel d'Andrada (dandrader)]

Can't reproduce it with trunk (released) versions of unity8 and qtmir.

[Daniel d'Andrada (dandrader)]

Ignore what I said earlier. I can reproduce the bug now.

[Daniel van Vugt (vanvugt)]

Ignore my comment about nautilus. That's just the nautilus desktop window (which is meant to appear) failing to render for some reason. Not related.

[Daniel van Vugt (vanvugt)]

The nautilus issue is bug 1672949.

[Launchpad Janitor (janitor)]

This bug was fixed in the package unity8 - 8.15+17.04.20170321-0ubuntu1

---------------
unity8 (8.15+17.04.20170321-0ubuntu1) zesty; urgency=medium

  [ Albert Astals Cid ]
  * Signal aboutToShow (LP: #1664578)
  * Support Panel top level items to be disabled (LP: #1670694)
  * Improve Launcher ←→ touch menu interaction (LP: #1667620, #1671069)
  * Fix real world submenus (e.g. kate) not getting their first item
    selected on open (LP: #1666859)

  [ Daniel d'Andrada ]
  * Really disable the window decoration when in staged mode (LP:
    #1670361)
  * Don't let clients resize their surfaces while in staged
    (phone/tablet) mode (LP: #1670390)
  * TopLevelWindowModel: don't put hidden windows in the model (LP:
    #1665286)

  [ Lukáš Tinkl ]
  * Reset always-show-osk gsetting on startup to default value (false
    atm)
  * Fix the restored-to position with Miral due to the state changes
    being async (LP: #1669819)
  * Add a cursor name fallback mapping "grabbing" -> "closedhand" for
    Breeze
  * Fix unsnapping a maximized window from the panel (LP: #1671721)
  * Disable altDrag feature outside windowed mode

  [ Michael Terry ]
  * Don't lock the screen for guest users or users in the nopasswdlogin
    group. (LP: #1644237)
  * Support GNOME-style logout DBus API (making the Logout, Reboot, and
    Shutdown launcher commands work) (LP: #1673229)

  [ Michael Zanetti ]
  * Add support for closing apps from the spread with "Q" (LP: #1670327)
  * hide "private" launcher quicklist entries when the greeter is locked
    (LP: #1667649)
  * add surface titles to launcher's quicklist (LP: #1661668)
  * properly reset the drawer state when cancelling a horizontal drag
    (LP: #1669536)
  * fix the focus moving correctly between launcher and drawer (LP:
    #1669880)
  * unfocus the drawer's textfield when it is moved (LP: #1669839)

  [ Pete Woods ]
  * Fix up indicators-client after refactoring (LP: #1672797)

 -- Michał Sawicz <email address hidden> Tue, 21 Mar 2017 10:58:13 +0000

[Michał Sawicz (saviq)]

So this is Invalid for Mir/MirAL?