Issue Summary

Connect app modules which render inside iframes can briefly render un-themed content before theming is initialized within the iframe. This applies to pages, dynamic macros, inline dialogs, and any other content rendered within an iframe.

The issue has been raised in the developer community and has been investigated within Atlassian. It is likely that Confluence will need to prevent showing the iframe entirely until it has been initialized.

This is reproducible on Data Center: N/A

Steps to Reproduce

1. Create a Connect app with a page, dynamic macro, or inline dialog that has adopted theming
2. Install the app on any Confluence site
3. Switch theme to "Dark"
4. Navigate to the location within Confluence containing the module created in Step 1
5. Observe brief "flash" of white/light content before the dark content is rendered

Expected Results

The Connect app is rendered in the chosen theme with no perceived rendering of un-themed content

Actual Results

A brief "flash" of white/light content before the themed content is rendered

Workaround

There is no perfect workaround but it is recommended to initialize theming as early as possible within the Connect app logic. See Connect Theming