Bugfix drag and drop

Author: itepifanio-shape

plotly/basedatatypes.py

@@ -4720,7 +4720,7 @@ def __getitem__(self, prop):
 
                 return validator.present(self._compound_props[prop])
             elif isinstance(validator, (CompoundArrayValidator, BaseDataValidator)):
-                if self._compound_array_props.get(prop, None) is None:
+                if not self._compound_array_props.get(prop, None):
                     # Init list of compound objects
                     if self._props is not None:
                         self._compound_array_props[prop] = [