Add missing returns after calling superclass events.

We fscked that up in 9668994046.

qutebrowser/widgets/tabwidget.py

@@ -130,9 +130,11 @@ class TabBar(QTabBar):
         """Override mousePressEvent to emit tabCloseRequested on rightclick."""
         if e.button() != Qt.RightButton:
             super().mousePressEvent(e)
+            return
         idx = self.tabAt(e.pos())
         if idx == -1:
             super().mousePressEvent(e)
+            return
         self.tabCloseRequested.emit(idx)
 
     def tabSizeHint(self, index):

qutebrowser/widgets/webview.py

@@ -548,6 +548,7 @@ class WebView(QWebView):
         if e.button() in (Qt.XButton1, Qt.XButton2):
             self._mousepress_backforward(e)
             super().mousePressEvent(e)
+            return
         self._mousepress_insertmode(e)
         self._mousepress_opentarget(e)
         super().mousePressEvent(e)