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• I have confirmed this bug exists on the latest version of pandas.

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Note: Please read this guide detailing how to provide the necessary information for us to reproduce your bug.

Update 2

• The issue seems to be Google Chrome and Microsoft Edge
• Jupyter Lab in Firefox correctly displays all of the styled rows and correctly renders an output HTML file.
• The question is then, what are the relevant settings in Chrome and Edge, or why doesn't this work in Chrome or Edge?

Original

Code Sample, a copy-pastable example

import pandas as pd
import numpy as np
from faker import Faker  # conda install -c conda-forge faker or pip install Faker

# for fake names
fake = Faker()

# test data
np.random.seed(365)
rows = 11000

# change 36 or 158 to test where the rows stop appearing
vals = {f'val{i}': np.random.randint(1, 11, size=(rows)) for i in range(1, 36)}
data = {'name': np.random.choice([fake.unique.name() for i in range(158)], size=rows),
        'cat': np.random.randint(1, 4, size=(rows))}
data.update(vals)

df = pd.DataFrame(data)

# used to create the mask for the background color
mean = df.groupby('cat').mean().round(2)

# calculate the mean for each name and cat
cat_mean = df.groupby(['name', 'cat']).mean()


def color(x):
    """Function to apply background color"""
    c1 = 'background-color: green'
    c = '' 
    # compare columns
    mask1 = x.gt(mean)
    # DataFrame with same index and columns names as original filled empty strings
    df1 =  pd.DataFrame(c, index=x.index, columns=x.columns)
    # modify values of df1 column by boolean mask
    df1.iloc[mask1] = c1
    display(df1)

    return df1

# displays the notebook in Jupyter
cat_mean.style.apply(color, axis=None)

# In PyCharm saving rendered styler to file
cm = cat_mean.style.apply(color, axis=None).set_precision(3).render()

with open('cm_test.html', 'w') as f:
    f.write(cm)

Problem description

• Given a large dataframe, in this case 474 rows x 35 columns, the applied styling does not correctly display for all rows in Jupyter or if saving the file to HTML.
  • 
• If the number of rows or columns increases beyond this size, then more rows aren't displayed properly
• We can see from the styling map, that the rows are correctly mapped with a background color, but it isn't displayed.
  • 
• If the number of rows or columns is reduced, then all of the rows display the correct styling.
• jupyterlab v3.0.11 and pandas v1.2.3
• In PyCharm 2021.1 (Professional Edition) Build #PY-211.6693.115, built on April 6, 2021 saving the redendered styler to a file has the same result, so this isn't just an issue with Jupyter.
• This issue is reproducible on two different systems that I have tried.
• If the shape is reduced to 471 rows × 35 columns or 474 rows × 34 columns, then all rows correctly display the highlighting.
• Associated Stack Overflow question.

Workaround

Split the DataFrame

• It's dissatisfying, but splitting the DataFrame, and applying the style will work, since if reduces the overall size.

cat_mean.iloc[:237, :].style.apply(color, axis=None)
cat_mean.iloc[237:, :].style.apply(color, axis=None)

Save to Excel

• All rows are displayed correctly with the highlight color when saving to Excel

test = cat_mean.style.apply(color, axis=None)
test.to_excel('test.xlsx', engine='openpyxl')

Expected Output

• All rows should display highlighting.

Output1 of pd.show_versions()

Update 1

• The following options produced the same results as the original attempts
  • Standard python console creating HTML file
  • PyCharm creating HTML file
  • Jupyter Lab displaying styled dataframe in a cell

Output2 of pd.show_versions()