Add a lost-focusproxy debug flag

qutebrowser/browser/webengine/webview.py

@@ -66,9 +66,10 @@ class WebEngineView(QWebEngineView):
         However, it sometimes isn't, so we use this as a WORKAROUND for
         https://bugreports.qt.io/browse/QTBUG-68727
         """
-        proxy = self.focusProxy()
-        if proxy is not None:
-            return proxy
+        if 'lost-focusproxy' not in objreg.get('args').debug_flags:
+            proxy = self.focusProxy()
+            if proxy is not None:
+                return proxy
 
         # This should only find the RenderWidgetHostViewQtDelegateWidget,
         # but not e.g. a QMenu

qutebrowser/qutebrowser.py

@@ -167,7 +167,7 @@ def debug_flag_error(flag):
         log-requests: Log all network requests.
     """
     valid_flags = ['debug-exit', 'pdb-postmortem', 'no-sql-history',
-                   'no-scroll-filtering', 'log-requests']
+                   'no-scroll-filtering', 'log-requests', 'lost-focusproxy']
 
     if flag in valid_flags:
         return flag