BUG: Render issue with <flux:content.render area="foo" /> in Workspace previews.

[SimonMayr]

I am using Flux Grid to render a Header on my Website. I have a Flux Configuration that looks like this:

<flux:grid>
    <flux:grid.row>
        <flux:grid.column name="headerItems" label="Header" colPos="1">
            <flux:form.variable name="allowedContentTypes" value="hwprovider_headeritem" />
        </flux:grid.column>
    </flux:grid.row>
</flux:grid>

and rendering it like this:

<flux:content.render area="headerItems" />

I am also using the Typo3 Workspace Module.

The issue i am facing is that if i move or edit the Header in a workspace, the Header-Items are missing in the Preview.
Specifically <flux:content.render area="headerItems" /> is not returning anything in the preview even tho there should be Header-Items.

Steps to reproduce the behavior:

1. Switch to a Workspace other than the Live-Workspace.
2. Edit or move a Content Element that has some "Child-Elements".
3. Generate a preview link and visit the preview site.
4. The "Child-Elements" are now missing in the preview.

I tested this in Typo3 v11 and v12 and with every version of this extension, and all versions had this issue.

If more information is needed, i can also provide some screenshots or try to explain the problem further.

Thanks for the time you guys put into this project.

Simon