eventfilter: Ignore QKeyEvents in ChildEventFilter

Based on crash reports, sometimes somehow a QKeyEvent gets lost in there.

qutebrowser/browser/eventfilter.py

@@ -6,11 +6,12 @@
 
 from qutebrowser.qt import machinery
 from qutebrowser.qt.core import QObject, QEvent, Qt, QTimer
+from qutebrowser.qt.gui import QKeyEvent
 from qutebrowser.qt.widgets import QWidget
 
 from qutebrowser.config import config
 from qutebrowser.utils import log, message, usertypes, qtutils
-from qutebrowser.keyinput import modeman
+from qutebrowser.keyinput import modeman, keyutils
 
 
 class ChildEventFilter(QObject):
@@ -69,6 +70,15 @@ class ChildEventFilter(QObject):
 
             child.installEventFilter(self._filter)
         elif event.type() == QEvent.Type.ChildRemoved:
+            if isinstance(event, QKeyEvent):
+                # WORKAROUND for unknown (Py)Qt bug
+                info = keyutils.KeyInfo.from_event(event)
+                log.misc.warning(
+                    f"ChildEventFilter: ignoring key event {info} "
+                    f"on {qtutils.qobj_repr(obj)}"
+                )
+                return False
+
             child = event.child()
             log.misc.debug(
                 f"{qtutils.qobj_repr(obj)}: removed child {qtutils.qobj_repr(child)}")