Unset _NET_WM_USER_TIME_WINDOW before destroying the window

Otherwise metacity was crashing when a QWindow was destroyed immediately
after being activated, because metacity was trying to select events
(XSelectInput) for the already destroyed m_netWmUserTimeWindow.

Task-number: QTBUG-24492
Change-Id: Iedbe7bdd6b26110ca8bec6f33525209ae551ffd5
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 1688fdf92b..7777820e93 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -369,6 +369,14 @@ void QXcbWindow::destroy()
     if (m_syncCounter && m_screen->syncRequestSupported())
         Q_XCB_CALL(xcb_sync_destroy_counter(xcb_connection(), m_syncCounter));
     if (m_window) {
+        if (m_netWmUserTimeWindow) {
+            xcb_delete_property(xcb_connection(), m_window, atom(QXcbAtom::_NET_WM_USER_TIME_WINDOW));
+            // Some window managers, like metacity, do XSelectInput on the _NET_WM_USER_TIME_WINDOW window,
+            // without trapping BadWindow (which crashes when the user time window is destroyed).
+            connection()->sync();
+            xcb_destroy_window(xcb_connection(), m_netWmUserTimeWindow);
+            m_netWmUserTimeWindow = XCB_NONE;
+        }
         connection()->removeWindow(m_window);
         Q_XCB_CALL(xcb_destroy_window(xcb_connection(), m_window));
     }
diff --git a/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp b/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp
index 90c96b4030..f4556f7e32 100644
--- a/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp
+++ b/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp
@@ -64,6 +64,8 @@ private slots:
     void touchCancelWithTouchToMouse();
     void orientation();
     void close();
+    void activateAndClose();
+
     void initTestCase()
     {
         touchDevice = new QTouchDevice;
@@ -632,5 +634,16 @@ void tst_QWindow::close()
     QVERIFY(b.close());
 }
 
+void tst_QWindow::activateAndClose()
+{
+    for (int i = 0; i < 10; ++i)  {
+       QWindow window;
+       window.show();
+       QTest::qWaitForWindowShown(&window);
+       window.requestActivateWindow();
+       QTRY_COMPARE(qGuiApp->focusWindow(), &window);
+    }
+}
+
 #include <tst_qwindow.moc>
 QTEST_MAIN(tst_QWindow);