Please review HR fix of bug 248319

http://netbeans.org/issues/show_bug.cgi?id=248319

A third party Look and Feel causes custom menu creation to fail in GUI 
builder, effectively disabling any context menu. It makes the GUI builder 
pretty much unusable. Although it is a bug in 3rd party component, there are 
surprisingly high number of users using it (many reports in 8.0, 8.0.1, 
8.0.2). Workaround is simple and safe (additional check for null). Similar one 
already implemented in bug 245600.

http://hg.netbeans.org/jet-main/rev/0ad8e2d4038a

Thanks,
Tomas