Interactive applications like GUIs are hard to debug with an integrated debugger: a simple breakpoint disturbs a GUIs control flow and can trigger events which without debugger wouldn't occur. I don't know about eclipse, but what I did when I programmed GUIs was dumping relevant info right in the GUI (label, textbox): Internal states, event trigger counts etc.
If all fails, there's always log-files. The latter has the advantage that you can detect race conditions (what did occur after what?).