[GTK3] Fix column header right-click menu popup

The popup_at_pointer method is only available in GTK >=3.22 so for
compatibility restore using popup method.

Right-clicking on column headers popped-up torrent menu so only show
this menu when in torrentview.

deluge/ui/gtk3/listview.py

@@ -346,7 +346,7 @@ class ListView(object):
 
     def on_treeview_header_right_clicked(self, column, event):
         if event.button == 3:
-            self.menu.popup_at_pointer()
+            self.menu.popup(None, None, None, None, event.button, event.get_time())
 
     def register_checklist_menu(self, menu):
         """Register a checklist menu with the listview.  It will automatically

deluge/ui/gtk3/torrentview.py

@@ -792,7 +792,7 @@ class TorrentView(ListView, component.Component):
         """This is a callback for showing the right-click context menu."""
         log.debug('on_button_press_event')
         # We only care about right-clicks
-        if event.button == 3:
+        if event.button == 3 and event.window == self.treeview.get_bin_window():
             x, y = event.get_coords()
             path = self.treeview.get_path_at_pos(int(x), int(y))
             if not path: