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Office 365: Developer Blog

Office Add-ins community call – February 13, 2019

The Office Add-ins community call is our monthly event for developers to connect in real-time with the folks who are building the Office Add-ins platform and JavaScript APIs. During this call, we share updates about new Office JavaScript APIs and provide tips about useful tools, samples, and resources for developing Office Add-ins.

February’s call featured the following presenters and topics:

  • Doug Mahugh, Senior Dev Writer, presented an overview of the Office Add-ins platform.
  • Kim Brandl, Senior Dev Writer, requested customer input about single sign-on (SSO) in Office Add-ins and about Office developer tools and resources.
  • Sudheer Maremanda, Senior Program Manager, discussed plans to implement the Edge WebView control for Office Add-ins and provided guidance about implications of this upcoming change for add-in developers.
  • Lance Austin, Software Architect and Developer at BXB Digital, shared insights from his experience with building Office Add-ins in recent years and highlighted key learnings from his Office JS developer journey.

Watch the call here.

View the presentation here.

The next Office Add-ins community call is on Wednesday, March 13, 2019 at 8:00AM PST. You can download a recurring calendar invite at

Engage with us

Are you interested in delivering a presentation during an upcoming Office Add-ins community call? Or would you be willing to provide feedback aimed at helping to improve the Office Add-ins documentation? If you answered yes to either (or both!) of these questions, please connect with us by completing this short survey form.


We welcome you to submit questions and topic suggestions in advance of each call by using our short survey form.  Here’s the Q&A for questions that were submitted for February’s call:

Will the Edge WebView control run in 64-bit?

Yes, the Edge WebView control will run in 64-bit.

I can see that single sign-on (SSO) has been disabled for add-ins in the store. Can add-ins that are installed via a manifest file in the Office 365 admin screen for Services & Add-Ins (i.e., via centralized deployment) use SSO?

SSO is still in preview for all add-ins, including those that are installed via AppSource (the store) and via tenant admins (centralized deployment). We currently evaluate AppSource submissions and do not allow add-ins into AppSource that use SSO, but we do not monitor add-ins installed via admins.

We are developing Excel content and task pane add-ins with Office.js. Is there a way to launch a 64-bit Internet Explorer process as the host of our add-ins instead of a 32-bit process? Or can we start separate host processes for every add-in?

It’s not possible for an add-in developer to control the Internet Explorer process(es) that are used by Office add-ins.

Is it possible to launch a content pane from the Office ribbon? It was possible for a period in the past then this option disappeared.

The ability to launch a content pane from the Office ribbon has never actually been available, with the exception being add-ins that shipped with the product (e.g., Bing Maps and People Chart). This is something we are evaluating to add in the future, right now with no clear timeline.

What are the size limits for the Task pane (width, height) for both Excel desktop and Excel online (ideally the maximum usable sizes for the UI)?

In Excel Online, the task pane cannot be resized. In Excel for Windows, you can observe maximum width of a task pane by manually resizing the task pane to its maximum allowed width. On a related note, this article in the “Design the UI” section of the docs contains info about default task pane sizes on various platforms.

Will Excel/Word/PowerPoint raise the “on save” event and allow add-ins to interact with the document at that point, and show a dialog? (similar to “on send” in Outlook on the Web add-ins, and coming to Outlook desktop, Mac).

We’ve been discussing how to enable the “on save” event, but the challenge now is that the product is switching to an auto-save mode, which would make “on save” a very chatty event. We’d love to learn more about the scenario you’re looking to implement with the “on save” event. If you haven’t done so already, please submit a request for this API feature in UserVoice, and include a description of your use case for this event. Thanks!

Is there a way to hide formulas in certain cells without protecting the sheet?

Maybe you want to create a very hidden sheet for that? Otherwise, there is no way. (The ability to hide formulas in certain cells of an otherwise non-hidden, non-protected sheet is not feasible using the Office JavaScript APIs.)

I need information about Office.js for PowerPoint. We’d like to convert an existing VSTO app to Office.js. The add-in manipulates objects on slides, so it must be able to identify objects on slides, move them, color them, etc. Are these types of actions possible in a PowerPoint add-in that’s built using Office.js?

The type of functionality you’ve described is not currently possible in PowerPoint with the Office JavaScript APIs. The team’s efforts have been primarily focused on expanding capabilities of Excel APIs and Outlook APIs recently, but we do intend to eventually expand capabilities for PowerPoint as well.

I’ve written an Outlook add-in in ASP.NET that interacts with my API servers from the code-behind and only uses JavaScript to interact with Outlook. Is this approach valid or something that shouldn’t be done? The add-in seems to work well, and I haven’t had performance issues.

The approach you’ve described is perfectly valid.

When will Outlook mobile support web add-ins in message compose mode and in calendar compose mode?

We’re unable to provide an estimate at this time but will announce broadly as soon as we have a timeline to share.

When will Outlook for Windows support the on-send feature?

We are tentatively targeting early Q2 2019 for on-send on Outlook for Windows. (This timeline is subject to change, of course.)

When I attempt to deploy an add-in in Office 365 via manifest, the ‘Next’ button is disabled (greyed-out). How can I proceed with deployment?

Guidance about centralized deployment can be found in here in the docs. If the docs don’t help to resolve your issue, please log an issue to report this problem in the OfficeDev/office-js GitHub repository, and please be sure to provide detailed repro steps.

Can the Yeoman Generator for Office Add-ins be updated such that when you run Yo Office (and choose TypeScript), the add-in project that’s created contains a function-file.ts with sample code for a UI-less function?

Please log an issue with this enhancement request in the OfficeDev/generator-office GitHub repository. In the meantime, the code samples in the Implement a UI-less button section of the Outlook add-in tutorial in the docs might be helpful.

In the add-ins projects that the Yeoman Generator for Office Add-ins (Yo Office) creates for Angular or React, Office.js JavaScript has not been working in the default templates.

Please log an issue to report this problem in the OfficeDev/generator-office GitHub repository, and provide info about repro steps, expected outcomes, and actual outcomes.

Is there a high-level timeline for when Excel custom functions will stop being for Insiders only?

The team is working hard on stabilization; we’ll announce a date for general availability of Custom Functions as soon as it’s known.

We want to define a custom UDF that uses Excel’s built in cube function i.e., MyCubeValue(…) that internally calls Excel’s cubevalue built-in functions. We want this ability in our C# VSTO add-in to develop custom functions.

The ability to call an Excel built-in function from a custom function within an Office Add-in is a feature in the Excel Custom Functions backlog, but won’t be available when Excel Custom Functions is first made generally available. Keep in mind that Office Add-ins (as described previously) are different than VSTO add-ins. Information about developing VSTO add-ins can be found here in the docs.

Any reason why Office.js nullifies the browser replace state and push state? I had to cache/restore those when using react-router. 
Information about this topic is available in this Stack Overflow thread:


From February’s call

Office Add-ins community call

Office Add-ins feedback