It's like this: you setup a View to use a certain Layer Combination, say "Structural". You later decide it's more expedient for your project to rename the layer combination, from "Structural" to "04 Structural", because in the listing of Layer Combinations, to the left of the Layer Settings window, the Layer Combinations are listed in alphabetical order by name, and you want "Structural" to appear fourth from the top, after "Surveyor", "Volumetrics" and "Architectural Plan".
So you rename as described above. Alas, your Views now don't know which Layer Combination they are supposed to use: they will now show for Layer Combination: "MISSING (Structural)".
Same goes for Model View Options: you rename them, they become disconnected from Views that had been using them.
Alex Zachopoulos
MacBook Pro 17" 2.4GHz, MacOS X 10.5.6, ArchiCAD 11 & 12, WinXP, Vista (well, not really Vista...)