TOC settings: fix possible crash (#7434)
TOC settings: fix possible crash (#7434)


koreader/koreader,poire-z/koreader,NiLuJe/koreader,Frenzie/koreader,mwoz123/koreader,poire-z/koreader,koreader/koreader,Frenzie/koreader,NiLuJe/koreader