Table cell border rendering different between Outlook versions.

[StewartExcl]

Provide required information needed to triage your issue

When adding a signature to Outlook on iOS with a partial colored cell border, it displays correctly but does not render the color when displayed in Outlook Classic on Windows.

As seen in Outlook iOS

The result seen in Outlook Classic Windows

Note - This doesn't happen when creating a message in New Outlook on Windows, but I have created a ScriptLab example that can be run in New Outlook in Windows or OWA that demonstrates the problem when viewing in the message in Outlook Classic.

More Information

The problem seems to be the changes that Outlook makes to the HTML after it is set, in this case to element.

Original HTML
<td align="left" style="padding:12px; border-top:none; border-right:none; border-bottom:none; border-left:solid 8px #F5F736; vertical-align:top; font-family:Calibri,Arial,sans-serif;">

Outlook on iOS 18.6 changes this to
<td dir="ltr" align="left" style="white-space: nowrap; border-width: medium medium medium 8px; border-style: none none none solid; border-color: currentcolor currentcolor currentcolor rgb(245, 247, 54); padding: 12px; vertical-align: top;">

New Outlook and OWA can render this correctly, but Outlook Classic renders to cell border with the wrong color.

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: Source Platform iOS v18.6, Destination Windows 11.
• Host [Excel, Word, PowerPoint, etc.]: Source Outlook, Destination Outlook Classic
• Office version number: Source: v5.2605.0, Destination v2601 (Build 19628.20166 Click-to-Run)
• Operating System: Source iOS v18.6, Destination Windows 11
• Browser (if using Office on the web): n/a

Expected behavior

The color of table cell borders should render the same in all Outlook versions. This works for complete cell borders but not when a single side is specified.

Current behavior

The cell border is shown but is set to the color black when displayed in Outlook Classic. It does display correctly in New Outlook and OWA.

Steps to reproduce

I've created a ScriptLab example that demonstrates the problem using New Outook for Windows or OWA.

1. In New Outlook or OWA, Run the Linked ScriptLab example that inserts a signature containing a <table> and a <td> element where the cell has a colored left border.
2. The signature should show with a colored bar on the left hand side.
3. Send the message and view it in Outlook Classic
4. The the bar of the left-hand-side will have lost its color and display as Black.

Link to live example(s)

1. Script Lab Example

Example Email Messages

Display differently in New Outlook and Outlook Classic

Sent from Outlook iOS v18.6.eml

Sent from Outlook iOS v18.6.msg

Provide additional details

1. Run the ScriptLab example in New Outlook or OWA (Windows although the original bug is for iOS)
2. After running the script to add a signature with a colored bar on the left, send it to someone.
3. Open the message in Outlook Classic.. the Colored bar seen in the original message will now display as Black.

Context

iOS customers are complaining messages aren't displaying correctly when sent from iOS.

[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• Outlook signature changes appearance after clicking on "Open in new window" #5285

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Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Modifying Signature HTML: Adjust the HTML of the signature to set the height of the td elements to auto attribute.

<td style="width: 448px; height: auto;">Hello Hello Hello</td>

Reference:

• Outlook signature changes appearance after clicking on "Open in new window" #5285 (comment)
• Outlook signature changes appearance after clicking on "Open in new window" #5285 (comment)

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[ndeleuze]

@StewartExcl, thanks for reporting this issue.

After careful consideration, our team has decided to not fix this issue in the short term. We recommend you to upvote or create a new Tech Community item, this will give us visibility of the commonality of it and will help with our prioritization. If we end up working on this issue, we will re-activate as needed.

In the meantime, since there are no current guidelines for HTML rendering between clients, I would recommend playing around with the HTML used in your Add-in signature to find an approach that works better across platforms.