code: private static boolean isValidStack(VdmThread thread)
  	{
  		final IDebugOptions debugOptions = thread.getDbgpSession().getDebugOptions();
  		if (debugOptions.get(DebugOption.ENGINE_VALIDATE_STACK))
  		{
  			thread.updateStack();
  			if (thread.hasStackFrames())
  			{
  				return thread.isValidStack();
  			}
  		}
  		return true;
  	}
docs: Tests if the specified thread has valid current stack. In some cases it is better to skip first internal
  location.
  
  @param thread
  @return