Fix issues saving/restoring active tab

Fixes #212

app/models.py

@@ -239,6 +239,20 @@ class Playlists(Base):
         session.add(self)
         session.flush()
 
+    @staticmethod
+    def clear_tabs(session: scoped_session, playlist_ids: List[int]) -> None:
+        """
+        Make all tab records NULL
+        """
+
+        session.execute(
+            update(Playlists)
+            .where(
+                (Playlists.id.in_(playlist_ids))
+            )
+            .values(tab=None)
+        )
+
     def close(self) -> None:
         """Mark playlist as unloaded"""
 

app/musicmuster.py

@@ -875,15 +875,23 @@ class Window(QMainWindow, Ui_MainWindow):
     def load_last_playlists(self) -> None:
         """Load the playlists that were open when the last session closed"""
 
+        playlist_ids = []
         with Session() as session:
             for playlist in Playlists.get_open(session):
                 if playlist:
                     _ = self.create_playlist_tab(playlist)
+                    playlist_ids.append(playlist.id)
             # Set active tab
             record = Settings.get_int_settings(session, "active_tab")
-            if record.f_int and record.f_int >= 0:
+            if record.f_int is not None and record.f_int >= 0:
                 self.tabPlaylist.setCurrentIndex(record.f_int)
 
+            # Tabs may move during use. Rather than track where tabs
+            # are, we record the tab index when we close the main
+            # window. To avoid possible duplicate tab entries, we null
+            # them all out now.
+            Playlists.clear_tabs(session, playlist_ids)
+
     def lookup_row_in_songfacts(self) -> None:
         """
         Display songfacts page for title in highlighted row