Partially-configured color palette can crash Spectrum

[Ashoat]

I didn't see this actually happen at the burn, but I heard about it second-hand from @budadcabrion. He said that Joe Block had accidentally crashed Spectrum by selecting a partially-configured color palette. I am not sure if @budadcabrion told me this or if it is was my own conclusion, but I think the faulty code was probably in a visualizer somewhere