crash after loading search and changing marker size

output below. cannot replicate and may be obviated by backend changes in 0.6.0.
 (multidex) [Melissas-MacBook-Air:~/multidex/multidex] melissarice% python multidex.py MCAM
Dash is running on http://Melissas-MacBook-Air.local:49303/

Exception on /_dash-update-component [POST]
Traceback (most recent call last):
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/pandas/core/indexes/base.py", line 3361, in get_loc
    return self._engine.get_loc(casted_key)
  File "pandas/_libs/index.pyx", line 76, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/index.pyx", line 108, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi", line 5198, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi", line 5206, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'err_avg'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/flask/app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/flask/app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/flask/app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/dash/dash.py", line 1079, in dispatch
    response.set_data(func(*args, outputs_list=outputs_list))
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/dash/dash.py", line 1010, in add_context
    output_value = func(*args, **kwargs)  # %% callback invoked %%
  File "/Users/melissarice/multidex/multidex/plotter/callbacks.py", line 514, in handle_main_highlight_save
    handle_graph_search(search_df, params, spec_model),
  File "/Users/melissarice/multidex/multidex/plotter/graph.py", line 461, in handle_graph_search
    return df_multiple_field_search(search_df, parameters)
  File "/Users/melissarice/multidex/multidex/multidex_utils.py", line 641, in df_multiple_field_search
    search_result = df_interval_search(
  File "/Users/melissarice/multidex/multidex/multidex_utils.py", line 597, in df_interval_search
    metadata_df[field]
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/pandas/core/frame.py", line 3455, in __getitem__
    indexer = self.columns.get_loc(key)
  File "/Users/melissarice/opt/miniconda3/envs/multidex/lib/python3.9/site-packages/pandas/core/indexes/base.py", line 3363, in get_loc
    raise KeyError(key) from err
KeyError: 'err_avg'
MillionConcepts / multidex

crash after loading search and changing marker size #8
