From the beginning, NetBeans debugger have problems with various threading problems producing exceptions like
IncompatibleThreadStateException and InvalidStackFrameException, which are hard to reproduce.
Having a test that is able to simulate concurrent debugger access and reproduce such errors seems to be essential for
locating the problem and creating the fix.
Some partial tests were written, but a complex test, that would contain e.g. parallel stepping, variable inspection and method invocation is still missing.