diff --git a/qutebrowser/config/config.py b/qutebrowser/config/config.py
index 0fb3fe450..11a7ba1ec 100644
--- a/qutebrowser/config/config.py
+++ b/qutebrowser/config/config.py
@@ -88,12 +88,12 @@ class Config(QObject):
 
     Signals:
         changed: Gets emitted when the config has changed.
-                 Args: the changed section and option.
+                 Args: the changed section, option and new value.
         style_changed: When style caches need to be invalidated.
                  Args: the changed section and option.
     """
 
-    changed = pyqtSignal(str, str)
+    changed = pyqtSignal(str, str, object)
     style_changed = pyqtSignal(str, str)
 
     def __init__(self, configdir, fname, parent=None):
@@ -326,7 +326,7 @@ class Config(QObject):
         else:
             if section in ['colors', 'fonts']:
                 self.style_changed.emit(section, option)
-            self.changed.emit(section, option)
+            self.changed.emit(section, option, self.get(section, option))
 
     @cmdutils.register(instance='config')
     def save(self):
@@ -459,12 +459,12 @@ class LineConfigParser:
         with open(self._configfile, 'w') as f:
             self.write(f, limit)
 
-    @pyqtSlot(str, str)
-    def on_config_changed(self, section, option):
+    @pyqtSlot(str, str, object)
+    def on_config_changed(self, section, option, value):
         """Delete the file if the limit was changed to 0."""
         if self._limit is None:
             return
-        if (section, option) == self._limit and config.get(*self._limit) == 0:
+        if (section, option) == self._limit and value == 0:
             if os.path.exists(self._configfile):
                 os.remove(self._configfile)
 
diff --git a/qutebrowser/widgets/browsertab.py b/qutebrowser/widgets/browsertab.py
index 16e097cce..b6b1a3270 100644
--- a/qutebrowser/widgets/browsertab.py
+++ b/qutebrowser/widgets/browsertab.py
@@ -176,7 +176,9 @@ class BrowserTab(QWebView):
         netman.deleteLater()
         logging.debug("Tab shutdown scheduled")
 
-    def on_config_changed(self, section, option):
+    # pylint: disable=unused-argument
+    @pyqtSlot(str, str, object)
+    def on_config_changed(self, section, option, value):
         """Update tab config when config was changed."""
         if section == 'general' and option in ['zoomlevels', 'defaultzoom']:
             self._init_neighborlist()
diff --git a/qutebrowser/widgets/completion.py b/qutebrowser/widgets/completion.py
index 713be2309..5d87c7410 100644
--- a/qutebrowser/widgets/completion.py
+++ b/qutebrowser/widgets/completion.py
@@ -211,11 +211,11 @@ class CompletionView(QTreeView):
         self.expandAll()
         self.resizeColumnToContents(0)
 
-    @pyqtSlot(str, str)
-    def on_config_changed(self, section, option):
+    @pyqtSlot(str, str, object)
+    def on_config_changed(self, section, option, value):
         """Update self._enabled when the config changed."""
         if section == 'general' and option == 'show_completion':
-            self._enabled = config.config.get('general', 'show_completion')
+            self._enabled = value
 
     @pyqtSlot(str)
     def on_cmd_text_changed(self, text):
diff --git a/qutebrowser/widgets/mainwindow.py b/qutebrowser/widgets/mainwindow.py
index 8053695c9..c53005515 100644
--- a/qutebrowser/widgets/mainwindow.py
+++ b/qutebrowser/widgets/mainwindow.py
@@ -20,7 +20,7 @@
 import binascii
 from base64 import b64decode
 
-from PyQt5.QtCore import QRect, QPoint
+from PyQt5.QtCore import pyqtSlot, QRect, QPoint
 from PyQt5.QtWidgets import QWidget, QVBoxLayout
 
 from qutebrowser.widgets.statusbar import StatusBar
@@ -99,7 +99,9 @@ class MainWindow(QWidget):
         #self.tabWidget.setCurrentIndex(0)
         #QtCore.QMetaObject.connectSlotsByName(MainWindow)
 
-    def on_config_changed(self, section, option):
+    # pylint: disable=unused-argument
+    @pyqtSlot(str, str, object)
+    def on_config_changed(self, section, option, value):
         """Resize completion if config changed."""
         if section == 'general' and option == 'completion_height':
             self.resize_completion()
diff --git a/qutebrowser/widgets/tabbar.py b/qutebrowser/widgets/tabbar.py
index 47b3455fb..9e3dbe6c7 100644
--- a/qutebrowser/widgets/tabbar.py
+++ b/qutebrowser/widgets/tabbar.py
@@ -99,8 +99,9 @@ class TabWidget(QTabWidget):
         except KeyError:
             pass
 
-    @pyqtSlot(str, str)
-    def on_config_changed(self, section, option):
+    @pyqtSlot(str, str, object)
+    def on_config_changed(self, section, option, value):
         """Update attributes when config changed."""
+        # pylint: disable=unused-argument
         if section == 'tabbar':
             self._init_config()
diff --git a/qutebrowser/widgets/tabbedbrowser.py b/qutebrowser/widgets/tabbedbrowser.py
index 94d10defd..c92e21b6c 100644
--- a/qutebrowser/widgets/tabbedbrowser.py
+++ b/qutebrowser/widgets/tabbedbrowser.py
@@ -139,12 +139,12 @@ class TabbedBrowser(TabWidget):
         else:
             return None
 
-    @pyqtSlot(str, str)
-    def on_config_changed(self, section, option):
+    @pyqtSlot(str, str, object)
+    def on_config_changed(self, section, option, value):
         """Update tab config when config was changed."""
-        super().on_config_changed(section, option)
+        super().on_config_changed(section, option, value)
         for tab in self._tabs:
-            tab.on_config_changed(section, option)
+            tab.on_config_changed(section, option, value)
 
     def _titleChanged_handler(self, text):
         """Set the title of a tab.