1. Project Properties -> Run/Debug/Profile -> Default (or whatever is your Run Configuration name) -> Edit... -> Java Options -> enter -XX:-UseSSE42Intrinsics in the text box.2. Edit to your <JDEV_HOME>/jdev/bin/jdev.conf and add this line: AddVMOption -XX:-UseSS42Intrinsics
Note that the Release Notes only talk about adding the option to WLS's runtime settings, but you also need it for design time as ADF Faces is being called behind the scenes to render the JSPX files in the IDE. I also recommend to turn on the "Show Design Time Messages in Log" option so you can see any error messages being raised by the JSP/HTML Visual Editor. Go to Preferences -> JSP and HTML Visual Editor panel to turn it on.