As of 3.1.3, using even the newest 3.1.4 js, if the player is loaded into a div that's css parameters contain visibility: hidden; at the time the player is loaded, i just get a black screen with a spinner once the css parameter is changed via javascript to make the div visible. This is a common method of creating panels with tabs or similar effects. Removing that parameter fixes it but makes it impossible to put a pre-loaded player on tabbed panels.