I get this when I have a bunch of peaks selected and I set sequential spin system. The same error goes away when I deselect the peaks and re-select them and then set the sequential spin system. This has been there for quite sometime and it has nothing to do with my previously reported error. Exception in Tkinter callback Traceback (most recent call last): File "/sw/lib/python2.4/lib-tk/Tkinter.py", line 1345, in __call__ return self.func(*args) File "/sw/share/ccpnmr/ccpnmr1.0/python/memops/gui/Menu.py", line 169, in <lambda> options_copy['command'] = lambda: func(self.menu_event) File "/sw/share/ccpnmr/ccpnmr1.0/python/ccpnmr/analysis/ WindowPopup.py", line 1041, in <lambda> 'command': lambda event, s=seqOffset: self.makeSeqSpinSystemConnections(s)}) File "/sw/share/ccpnmr/ccpnmr1.0/python/ccpnmr/analysis/ WindowPopup.py", line 3937, in makeSeqSpinSystemConnections addPeakResonancesToSeqSpinSystems(peak, seqOffsets) File "/sw/share/ccpnmr/ccpnmr1.0/python/ccpnmr/analysis/ AssignmentBasic.py", line 2022, in addPeakResonancesToSeqSpinSystems if spinSystem and spinSystems[i]: IndexError: list index out of range