Sometimes it can be handy to know if a Composer function is placed directly on the page or if it's placed in another Composer function. Here is a piece of code I wrote that does the trick.
The property must be placed in a class that derives from Dropit.Extension.Core.BaseContentFunction

private bool ParentIsContentFunction
{
    get
    {
        // Make sure that the current page is an Composer page
        if (this.CurrentExtensionPageData != null)
        {
            ContentFunctionData currentContentFunctionData = new ContentFunctionData(this.ContentFunctionLink);
            
            // Loop through all content areas in the page
            foreach(ContentAreaData ca in this.CurrentExtensionPageData.ContentAreas)
            {    
                // If any of the content areas contains the current content function it means that the function is placed directly on the page
                // - it's not placed in another content function
                if (ca.ContentFunctions.Contains(currentContentFunctionData))
                    return false;
            }
        }
        
        // If we reach this code it means that the content function is placed in another content function
        return true;
    }
}