Eclipse won't break in threads

Question

I'm using Eclipse to develop a PyQt application using PyDev. It's using two threads, one for gui and one for network traffic and Eclipse refuse to break on breakpoints set in the network traffic thread, I know it runs because it's throwing exceptions but I can't inspect things which is highly annoying.

Has anybody else experienced similar problems? Pseudocode:

 class NetHelper
     sendLots()

 class Worker(QThread):
     run()
        NetHelper.sendLots()

 class GUIThingie(QDialog):
     handleClick():
         self.worker.start()