1. The NetBeans GUI editor stinks. If you absolutely refuse to build your GUI's by hand (see #2), use JBuilder Foundation.
2. Build your GUI's by hand. You can write them much more efficiently (both performance-wise and object-oriented-wise) than any code generator can.
3. Code that imports on a per class basis is more readable.
But to answer your question, I don't believe you can turn that off in NetBeans, though I haven't used it for about a year. I've been in JBuilder heaven since 2005 was released.