I have tested my code on Windows, Solaris and Linix. All fine. On an OS-X Mac, I get two problems:

1) My JButtons (which I use for network nodes in a null layout manager JFrame) have no color (which I use to identify the node type). They do get color if the Java L&F is used. Why doesn't the Mac L&F support colored buttons?

2) I get lots of null pointer references when I drag the buttons. It occurs when the phantom rectangle gets drawn. I check that the rectangle is not null before I draw it, and the null pointer occurs in the Apple drawing guts...

I think these are Mac bugs. Or am I wrong? How do I tell?