Update the pane's filter when updating the start date of a task

.gitignore

@@ -35,3 +35,6 @@ flatpak/bundles
 
 # src/ usually has development version of liblarch
 src/
+
+# Python virtual environments
+venv*/

GTG/gtk/browser/main_window.py

@@ -1033,6 +1033,11 @@ def update_start_date(self, widget, new_start_date):
         for task in self.get_pane().get_selection():
             task.date_start = new_start_date
 
+        # Changing the start date of a task may take it out of the current pane
+        # (e.g. setting the start date of an Actionable task to tomorrow)
+        # See #1039
+        self.get_pane().task_filter.changed(Gtk.FilterChange.DIFFERENT)
+
     def update_start_to_next_day(self, day_number):
         """Update start date to N days from today."""
 
@@ -1041,6 +1046,11 @@ def update_start_to_next_day(self, day_number):
         for task in self.get_pane().get_selection():
             task.date_start = next_day
 
+        # Changing the start date of a task may take it out of the current pane
+        # (e.g. setting the start date of an Actionable task to tomorrow)
+        # See #1039
+        self.get_pane().task_filter.changed(Gtk.FilterChange.DIFFERENT)
+
 
     def on_mark_as_started(self, action, param):
         self.update_start_date(None, "today")