Merge pull request #347 from scipp/remove_nodes_when_removing_shapes

Remove old unused nodes that were left over when removing shapes

src/plopp/widgets/drawing.py

@@ -98,7 +98,7 @@ def update_node(self, artist):
 
     def remove_node(self, artist):
         nodeid = artist.nodeid
-        draw_node = self._draw_nodes[nodeid]
+        draw_node = self._draw_nodes.pop(nodeid)
         output_node = self._output_nodes[nodeid]
         if self._destination_is_fig:
             self._destination.artists[output_node.id].remove()