How can I check in a Component whether another related Component exists on the page?
My Blog components need to have the ConfigureBlog Component on the page. If it isn’t added I would like flag that up in the Editor as being missing.
I was thinking of related Components checking for a property in the ConfigureBlog Component and then displaying a warning DIV between an ‘@if(edit) | @endif’ pair if it was missing?
Hmmm, I’m not sure what the best way to do this would be 
I’ll message the rest of the team and see if they have any ideas on doing this…
We don’t have a good solution right now, however we have a few ideas on how to handle this like automatically adding a “settings” component to the page when a component is added that requires it.
In the past, other editors have shown the warning in related components, and use some CSS in the configure component to hide it - it works but it’s not a great solution.
In the related component you might have this
<div class="com-realmac-blog-configure-error">
NEEDS CONFIGURE COMPONENT
</div>
And in the configure component you could have this
<style>
.com-realmac-blog-configure-error { display: none; }
</style>
Just be careful to use a unique class name to control the visibility like I’ve done above.