Fix event filter when a non-Mainwindow dialog has an event.

qutebrowser/keyinput/modeman.py

@@ -121,7 +121,7 @@ class EventFilter(QObject):
                                  window='current')
             return modeman.eventFilter(obj, event)
         except objreg.RegistryUnavailableError:
-            # No window available yet
+            # No window available yet, or not a MainWindow
             return False
         except:
             # If there is an exception in here and we leave the eventfilter

qutebrowser/utils/objreg.py

@@ -99,7 +99,10 @@ def _get_registry(scope, window):
         widget = tabbed_browser.currentWidget()
         if widget is None:
             raise RegistryUnavailableError(scope)
-        return widget.registry
+        try:
+            return widget.registry
+        except AttributeError:
+            raise RegistryUnavailableError(scope)
     elif scope == 'window':
         if window is None:
             raise TypeError("window is None with scope window!")
@@ -113,7 +116,10 @@ def _get_registry(scope, window):
                 win = window_registry[window]
             except KeyError:
                 raise RegistryUnavailableError(scope)
-        return win.registry
+        try:
+            return win.registry
+        except AttributeError:
+            raise RegistryUnavailableError(scope)
     elif scope == 'meta':
         return meta_registry
     else: