Thank you for your feedback, we are happy to announce that the capability to message a dialog from the task pane is now available in preview. Please follow this link to get further information: https://docs.microsoft.com/en-us/office/dev/add-ins/develop/parent-to-dialog
With this API, the task pane can now message the dialog as well, pairing with the existing API allowing the dialog to message the task pane.
An error occurred while saving the commentMarc Kellison commented
Agreed. A much needed feature.