Throw exception if SpecialColumnPosition is set after IsLoaded.
Throw exception if SpecialColumnPosition is set after IsLoaded.

2yangk23/osu,naoey/osu,johnneijzen/osu,NeoAdonis/osu,smoogipooo/osu,NeoAdonis/osu,peppy/osu-new,EVAST9919/osu,Drezi126/osu,DrabWeb/osu,Frontear/osuKyzer,ppy/osu,Nabile-Rahmani/osu,ppy/osu,peppy/osu,UselessToucan/osu,peppy/osu,UselessToucan/osu,smoogipoo/osu,ZLima12/osu,nyaamara/osu,EVAST9919/osu,UselessToucan/osu,smoogipoo/osu,smoogipoo/osu,ZLima12/osu,johnneijzen/osu,ppy/osu,2yangk23/osu,DrabWeb/osu,Damnae/osu,NeoAdonis/osu,DrabWeb/osu,naoey/osu,tacchinotacchi/osu,naoey/osu,peppy/osu,osu-RP/osu-RP