Layout is broken, what to do?
In this example if our plugin look like this:
Go to your Dashboard -> Pages and open the page that contain the Stachethemes Event Calendar shortcode.
Open in Text mode and see if the shortcode is wrapped in PRE tag like this:
If this is the case, remove them and update the page. If this don't fix the problem you are having please open a ticket and we will take look at it :)
Video of the steps explained can be seen here: