Confluence Editor - Insert image dialog calles non-existing messenger function

During our plugin development we faced the following error.

1.) Our plugin get the uploaded content to be checked before storage. If there might be some configuration not allowing the storage the plugin sends an error back.

2.) If we call on a page > Edit > Insert > Image and drag/drop an image into the dialog Dnd area, the content get checked as expected. BUT: In case of sending an error back (Status Code: 500 with including error message) the following code throws an error:

displayErrors: function()

{ messenger.displayErrors(); }

,

As far as we can figure it out the called function "displayErrors" does not exists in the messenger object. Therefore the error sent by our plugin will not be shown to the client.

File Name: insert-image-dialog-attachments.js
Code Path:
confluence-x.x.x-source\confluence-project\confluence-plugins\confluence-editor-plugins\confluence-editor\src\main\resources\js

It would be very helpful to get this checked by you.

Thanks in advance,
Sabine Winkler