uiless action in Outlook add-in with displayDialog() - outlook

Question

We are seeing a change in Outlook with one of actions (“Help”) that stopped working on the web client only.
This action simply calls a js that opens a web page in a displayDialog() but it’s uiless in the sense that there’s no pane.
The other action (“Sign”) works ok but it launches a pane that does this.
Both of them work fine on the rich client (at least the version I use).
I wonder if there has been in recent changes in the requirements or the way this works?
We’re not seeing any error messages, just nothing happens after the prompt saying that the add-in is doing something.

Answer 1

We did some initial testing and noticed that in chrome the dialog will sometimes appear briefly. Could you confirm that you are calling event.completed() in the eventhandler of EventType.DialogEventReceived? event.completed() must be called in the DialogEventReceived handler otherwise the dialog will be closed prematurely.
Office.context.ui.displayDialogAsync(url, dialogOptions, function(result) {
// In the callback, save the dialog object
dialog = result.value;
// Add an event handler for messages sent via messageParent
dialog.addEventHandler(Microsoft.Office.WebExtension.EventType.DialogMessageReceived, receiveMessage);
// Add an event handler for events from the platform (like closing the dialog, etc.)
dialog.addEventHandler(Microsoft.Office.WebExtension.EventType.DialogEventReceived, dialogClosed);
});