I only noticed this on a Win10 Surface Pro 4 (fully updated, Java 8u73 to 8u101), but through Firefox, IE, and Chrome, was unable to launch Designer with javaws. Client launchers worked fine. After spending way too long messing with security settings and such, I decided to change the Designer memory allocation on the Gateway from 2GB to 1GB and suddenly the designer launched as expected.
Hadn’t seen this phenomenon at all on Win7 machines with same Java versions, but figured I’d post this here in case someone has thoughts on why this occurs or had the same problem.