Disconnect tabMoved signal for performance

tree-tab-collapse in particular was very slow because update_tab_titles
was called undreds of times for large trees.

qutebrowser/mainwindow/tabwidget.py

@@ -67,8 +67,7 @@ def __init__(self, win_id, parent=None):
         self.setStyle(TabBarStyle())
         self.setTabBar(bar)
         bar.tabCloseRequested.connect(self.tabCloseRequested)
-        bar.tabMoved.connect(functools.partial(
-            QTimer.singleShot, 0, self.update_tab_titles))
+        bar.tabMoved.connect(self.update_tab_titles)
         bar.currentChanged.connect(self._on_current_changed)
         bar.new_tab_requested.connect(self._on_new_tab_requested)
         self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Fixed)
@@ -249,6 +248,7 @@ def _toggle_visibility(self):
 
     def update_tab_titles(self):
         """Update all texts."""
+        log.misc.debug('update_tab_titles')
         with self._toggle_visibility():
             for idx in range(self.count()):
                 self.update_tab_title(idx)

qutebrowser/mainwindow/treetabwidget.py

@@ -35,6 +35,7 @@ def __init__(self, win_id, parent=None):
         # root of the tab tree, common for all tabs in the window
         self.tree_root = Node(None)
         super().__init__(win_id, parent)
+        self.tabBar().tabMoved.disconnect(self.update_tab_titles)
 
     def _init_config(self):
         super()._init_config()
@@ -72,8 +73,8 @@ def update_tree_tab_positions(self):
 
     def tree_tab_update(self):
         """Update titles and positions."""
-        self.update_tab_titles()
         self.update_tree_tab_positions()
+        self.update_tab_titles()
 
     def tabRemoved(self, idx):
         """Call tree_tab_update after super().tabRemoved."""