fix error when opening card layout
fix error when opening card layout

kenjhim/anki,LucasCabello/anki,jkitching/anki,jakesyl/ruby-card,Stvad/anki,xuewenfei/anki,sunclx/anki,weihautin/anki,hssm/anki,eduOS/anki,subfusc/anki,socialpercon/anki-1,holycrepe/anki,weihautin/anki,Arthaey/anki,hssm/anki,florianjacob/anki,abeyer/anki,jakesyl/ruby-card,go38/anki,ospalh/libanki3