This issue has been found by a SB customer that added a blank char to the effect syntax. This has the bad side effect to make FX Thread to deal with an untapped Exception when CSS is applied (class cast exception String, expected Effect)

I attached a simple test case, the faulty syntax is: -fx-effect: dropshadow ( one-pass-box , black , 8 , 0.0 , 5 , 10 );

Until now, we have worked at making CSS error non fatal in order to preserve SB. This exception path has been missed.