Streamlit Data Editor: Fixing Date And Time Icon Theme Colors

Dec 3, 2025 by Alex Johnson 62 views

Have you ever noticed that the date and time icons in your Streamlit st.data_editor don't quite match your application's carefully chosen theme? You're not alone! This article dives into a specific issue where the date and time icons within the Streamlit data editor fail to inherit the color scheme defined by your application's theme. We'll explore the problem, provide a reproducible code example, discuss the expected behavior, and outline the current behavior. Let's get started on understanding and addressing this theming quirk in Streamlit.

The Issue: Date and Time Icons Ignoring Theme Colors

The core problem lies in how the date and time icons within the st.data_editor component handle color theming. While Streamlit generally does an excellent job of applying your chosen theme (whether it's a light or dark mode, or a custom color palette) to various elements, these specific icons seem to have a mind of their own. A recent fix aimed to improve the visibility of these icons in dark mode inadvertently hardcoded their colors, preventing them from adapting to the overall theme. This results in a visual disconnect, where the icons clash with the rest of your application's aesthetics. The importance of consistent theming cannot be overstated, as it directly impacts the user experience and the perceived professionalism of your application. When elements like icons don't align with the overall color scheme, it can create a jarring effect and detract from the user's focus on the content itself. Therefore, ensuring that all components, including these date and time icons, properly inherit and reflect the defined theme is crucial for a polished and cohesive user interface. This attention to detail not only enhances the visual appeal but also contributes to a more intuitive and user-friendly experience, making the application more enjoyable and effective to use.

Reproducing the Issue: A Code Example

To illustrate this issue, let's walk through a reproducible code example using Streamlit. This will allow you to see firsthand how the problem manifests and understand the steps to recreate it. By providing a clear and concise example, we can ensure that everyone is on the same page regarding the issue and its potential impact on Streamlit applications.

Below is a Python code snippet that you can run within a Streamlit application to observe the problem:

from datetime import datetime
import pandas as pd
import streamlit as st

data_df = pd.DataFrame(
    {
        "appointment": [
            datetime(2024, 2, 5, 12, 30),
            datetime(2023, 11, 10, 18, 0),
            datetime(2024, 3, 11, 20, 10),
            datetime(2023, 9, 12, 3, 0),
        ]
    }
)

st.data_editor(
    data_df,
    column_config={
        "appointment": st.column_config.DatetimeColumn(
            "Appointment",
            min_value=datetime(2023, 6, 1),
            max_value=datetime(2025, 1, 1),
            format="D MMM YYYY, h:mm a",
            step=60,
        ),
    },
    hide_index=True,
)

To reproduce the issue, follow these steps:

Create a Streamlit application and paste the code above into your app.py file (or any other Python file you use for your Streamlit app).
Create a config.toml file in the same directory as your app.py file. This file will be used to define the theme for your Streamlit application. Add the following content to your config.toml file:
```
[theme]
base="dark" # Or "light"
textColor="red" # Or any other color
```
Run your Streamlit application using the command streamlit run app.py in your terminal.
Once the application is running, you'll see a data editor with a column named "Appointment" containing date and time values.
Double-click in a cell within the "Appointment" column to activate the editor. You'll notice the date and time icons that appear next to the input field.

By following these steps, you should be able to reproduce the issue and observe how the date and time icons do not inherit the textColor defined in your config.toml file. The icons will likely remain white in dark mode and black in light mode, regardless of the textColor you've specified. This discrepancy highlights the theming issue we're addressing in this article.

Expected vs. Current Behavior

Let's clarify what we expect to see versus what actually happens in this scenario. This comparison is crucial for understanding the scope of the problem and the desired outcome. When discrepancies arise between expected and current behavior, it often indicates a bug or an area where improvement is needed. In this case, the theming of date and time icons in the Streamlit data editor is the focus of our attention.

Expected Behavior

The ideal scenario is that the date and time icons within the st.data_editor should seamlessly integrate with the application's theme. This means:

The color of the icons should dynamically adapt to the textColor defined in the config.toml file (or the default theme colors if no custom color is specified).
Whether you're using a light or dark theme, the icons should maintain sufficient contrast against the background to ensure visibility.
The editing color (the highlight color when a cell is selected for editing) should also align with the theme, providing a consistent visual experience.

In essence, the icons should be thematically consistent with the rest of the application, creating a cohesive and visually appealing user interface. This consistency is paramount for a professional and user-friendly application.

Current Behavior

Unfortunately, the current behavior deviates from this ideal. As observed in the reproducible code example, the date and time icons exhibit the following characteristics:

The icon color is hardcoded based on the base theme (light or dark) and does not respond to the textColor setting in the config.toml file.
In dark mode, the icons appear white, while in light mode, they appear black, regardless of the desired text color.
The editing color (the text color and highlight within the editing cell) is also inconsistent. In both light and dark modes, the editing text is black with a blue highlight, which may not align with the overall theme.

This behavior leads to a visual disconnect, where the icons and editing color clash with the intended theme, creating a less polished and potentially confusing user experience. The lack of theming on these icons stands out, especially in applications where a custom color palette is used to create a unique brand identity.

Diving Deeper: Root Cause and Potential Solutions

To effectively address this issue, it's essential to delve into the potential root cause and explore possible solutions. Understanding why this is happening will guide us toward a more robust and lasting fix. Let's analyze the situation and brainstorm some strategies for resolving the theming inconsistency.

Potential Root Cause

The most likely reason for this behavior is that the color of the date and time icons was hardcoded during a previous fix. As mentioned earlier, a recent effort to improve the visibility of these icons in dark mode may have inadvertently set their color to a specific value (white for dark mode, black for light mode) without considering the overall theme. This is a common pitfall in software development, where a targeted fix can sometimes have unintended side effects if not carefully implemented. The hardcoding of colors bypasses the theming system, preventing the icons from dynamically adapting to the user's chosen color scheme. This approach, while seemingly straightforward in the short term, creates a long-term maintenance issue, as any changes to the theme will not be reflected in these hardcoded elements.

Potential Solutions

Several approaches can be taken to rectify this theming issue. Here are a few potential solutions:

Remove the Hardcoding: The most direct solution is to identify and remove the hardcoded color values for the date and time icons. Instead, the code should be modified to retrieve the appropriate color from the Streamlit theme configuration. This would ensure that the icons inherit the textColor or other relevant theme colors.
Utilize CSS Variables: Streamlit leverages CSS variables for theming. The icon colors could be tied to specific CSS variables that are updated based on the selected theme. This approach provides a flexible and maintainable way to manage theming across the application.
Create a Theming API for Components: Streamlit could provide a more explicit API for components to access and utilize theme information. This would make it easier for component developers to ensure that their elements are properly themed and consistent with the overall application style.
Contribute to Streamlit: If you're comfortable with Python and web development, consider contributing a fix directly to the Streamlit library. You can submit a pull request with the corrected code, benefiting the entire Streamlit community.

By implementing one or more of these solutions, we can ensure that the date and time icons in the st.data_editor seamlessly integrate with the application's theme, providing a more polished and user-friendly experience. The key is to adopt a dynamic theming approach, where colors and styles are driven by the theme configuration rather than being hardcoded.

Conclusion: Ensuring a Cohesive User Experience

In conclusion, the issue of date and time icons not adopting theme colors in Streamlit's st.data_editor highlights the importance of consistent theming for a cohesive user experience. While a previous fix aimed to improve icon visibility in dark mode, it inadvertently hardcoded the colors, preventing them from adapting to the application's overall theme. This can lead to a visual disconnect and detract from the user's perception of the application's polish and professionalism.

By understanding the root cause – the hardcoding of colors – and exploring potential solutions such as removing the hardcoding, utilizing CSS variables, or creating a theming API for components, we can work towards resolving this issue. The goal is to ensure that all elements within a Streamlit application, including these often-overlooked icons, seamlessly integrate with the chosen theme, providing a visually appealing and user-friendly interface.

The Streamlit community is known for its collaborative spirit, and addressing this theming inconsistency will undoubtedly benefit many developers and users. By contributing to the project or implementing these solutions in your own applications, you can play a part in enhancing the overall Streamlit experience.

For more information on Streamlit theming and customization, you can visit the official Streamlit documentation and community forums. You might also find helpful resources on web development best practices for theming and CSS variables. Remember, a well-themed application is not just visually pleasing; it's also more intuitive and enjoyable to use.

For further reading on Streamlit theming and customization, check out the official Streamlit documentation on streamlit.io.