Troubleshooting CSS Overflow Issue in Salesforce Lightning-Record-Picker Component

Fixing Overlay Issues in Record Picker Components Within HTML Tables

When incorporating advanced UI components such as a record picker within an HTML table, one common issue developers encounter is the dropdown list getting hidden or clipped by other table elements. This significantly affects user experience, as the list should ideally overlay adjacent contents smoothly, showing all available choices irrespective of the underlying DOM structure. Here’s how I resolved this problem in a recent project.

Understanding the Problem

In my project, the user types into a record picker to search for parts, and a dropdown is supposed to show matching search results. However, instead of overlaying other elements, the dropdown got partly obstructed by elements underneath it. This behavior occured because the table was forcing its children elements to adhere to its overflow and stacking context restrictions.

Diagnosing CSS Behaviors

To troubleshoot, I first looked at the CSS properties associated with the table and its nested elements. Specifically, overflow: auto on the .table_component class stood out. This property was restricting the visibility of any extended part of the children (like a dropdown) that ventured outside the table’s physical boundaries.

CSS Adjustments

The record picker dropdown needs a higher stacking context to make it visible above all other elements. Initially, I tried playing around with the z-index property, but it didn’t solve the issue since the overflow: auto on the table container still clipped the overflowed content.

I needed an approach that would allow the dropdown to escape the clipping effect caused by the table’s overflow property.

Revising HTML and CSS

To achieve the desired overlay effect, I revised the HTML structure by providing absolute positioning context to the dropdown. I wrapped the lightning-record-picker element in a new div with a class of picker-wrapper set for controlling its position.

Here’s the revised portion of the HTML structure:

<td>
    <div class="picker-wrapper">
        <lightning-record-picker placeholder="Search Parts" variant="label-hidden"
            label="Select Part" object-api-name="Product2" matching-info={matchingInfo}
            display-info={displayInfo} filter={filter}
            onchange={handlePartPicker}></lightning-record-picker>
    </div>
    <!-- Additional content remains unchanged -->
</td>

And the updated CSS:

.picker-wrapper {
    position: relative;
}

.lightning-record-picker {
    position: absolute;
    z-index: 9999; /* Ensures the dropdown is above other content */
    width: 100%;
}

Adjustments for Responsive Handling

To ensure that this setup works seamlessly across different screen sizes, further media queries might be necessary. For example, adjusting the width of the .lightning-record-picker based on the viewport size ensures that the dropdown doesn’t extend unnecessarily or gets too squeezed.

Final Tweaks

After these adjustments, I tested across several browsers and adjusted z-index values to ensure no unintended layering occurred. I also made sure that the interaction with other form elements remained unaffected.

This solution effectively resolved the overlay issue by allowing the record picker dropdown to float above all other table elements, thus improving the usability of the component without redesigning the underlying table structure. Adjusting the CSS for absolute positioning while controlling the stacking context proved crucial in achieving the desired overlay effect in the UI.