I have menu item with content that is only available to registered users. Normaly if guest clicks it, standard joomla login shows - but is it possible to show modal popup instead as if login button would be clicked?
The SCLogin module doesn't have that ability. It's a nice idea, but there's a lot that has to be done 'under the hood' to check every link that's rendered on the page to determine if it *would be* reachable if the user clicks on it. That's a bit of overhead and would only work if the links are generated properly using the Joomla router and not hard-coded links to a specific URL.
We definitely like the possibility though and may try to investigate implementing such a feature.