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DataTable error: Invalid argument `fixed_columns` passed into DataTable

I get this error:

Invalid argument `fixed_columns` passed into DataTable with ID "sys_table".
Value provided: 
    "headers": true,
    "data": 1

With this code:

    table = dash_table.DataTable(
        columns=[{"name": name, "id": col} for name, col in zip(headers,
        fixed_rows = {'headers': True, 'data': 0},
        fixed_columns = {'headers': True, 'data': 1},
        style_cell_conditional=[{"if": {"column_id": "Specs"},
                                 "textAlign": "left"}],
        style_table={'overflowX': 'scroll', 'maxHeight': '600px',
                     'maxWidth': '1500px', 'overflowY': 'scroll'},
        style_cell={"padding": '0 2rem', 'border': 'none', 'minWidth': '200px',
                    'width': 'auto', 'height': 'auto', 'whiteSpace': 'normal'},
        style_header={'font_size': '20px', 'text_align': 'left',
                      'backgroundColor': colors['table_header_background'],
                      'color': colors['bright_text'], 'fontWeight': 'bold'},
        style_data={'font_size': '18px', 'text_align': 'left',
                    'backgroundColor': colors['table_background_1'],
                    'color': colors['bright_text']},
        style_data_conditional=[{'if': {'row_index': 'odd'},
                                 'backgroundColor': colors[

I am using dash-table v. 4.11.0. I am following the guidelines in DataTable docs. What am I doing wrong?

Hi diegos,
I don’t see any wrong in 'fixed_columns = {‘headers’: True, ‘data’: 1}'
If you remove that property, is the table shown as expected?

If I remove the property it the error disappears but the tables first column and row are not fixed. If I pass an empty dict:

fixed_columns = {}

also no error and no fixed col and row.

Sorry, you are saying that if you remove only the ‘fixed_column’ the ‘fixed_row’ do nothing? it do not fix the headers?

correct, it doesn’t seem to work at all.

:thinking: so strange!
Now you know that you have two problems instead of one. :grinning_face_with_smiling_eyes:
I thought perhaps the problem was to use both together but even with one is not working.
I have no clue. Sorry.

Change the fix_row to fixed_rows={‘headers’: True},

Hi @diegos

Just to make sure everything is set up right - try running this minimal working example:

import dash
import dash_table
import pandas as pd

df = pd.read_csv('')

app = dash.Dash(__name__)

app.layout = dash_table.DataTable(
    columns=[{"name": i, "id": i} for i in df.columns],
    fixed_columns = {'headers':True, 'data':1},
    fixed_rows = {'headers': True, 'data': 1},

if __name__ == '__main__':

If this works, then try checking the callback (I’m assuming you are using a callback to update the fixed_columns ). You will get this error if you return this:

[{'headers':True, 'data':1}]

If it still doesn’t work, try posting a minimal example that reproduces the error - complete with some sample data, and someone might be able to see what’s wrong.

Hopefully this will help :slight_smile: