Don't scroll display after drop

With no code, display scroll back to where the source rows came from.
With code we had, we ensured dropped rows were visible, but display
would still scroll.
Now freeze display as it is when rows are dropped.

app/playlists.py

@@ -233,6 +233,7 @@ class PlaylistTab(QTableWidget):
         if not event.source() == self:
             return  # We don't accept external drops
 
+        top_row = self.rowAt(0)
         row_set = set([mi.row() for mi in self.selectedIndexes()])
         targetRow = self.indexAt(event.position().toPoint()).row()
         row_set.discard(targetRow)
@@ -262,11 +263,10 @@ class PlaylistTab(QTableWidget):
         for row in reversed(sorted(rowMapping.keys())):
             self.removeRow(row)
         self.resizeRowsToContents()
-        event.accept()
-
         # Scroll to drop zone
-        self.scrollToItem(self.item(targetRow, 1),
-                          QAbstractItemView.ScrollHint.PositionAtCenter)
+        self.scrollToItem(self.item(top_row, 1),
+                          QAbstractItemView.ScrollHint.PositionAtTop)
+        event.accept()
 
         # Reset drag mode to allow row selection by dragging
         self.setDragEnabled(False)