Fix checkbox delete bug. (marisaleung)
Fix checkbox delete bug. (marisaleung)

gengshenghong/scratch-blocks,griffpatch/scratch-blocks,LLK/scratch-blocks,LLK/scratch-blocks,griffpatch/scratch-blocks,LLK/scratch-blocks,gengshenghong/scratch-blocks,LLK/scratch-blocks,gengshenghong/scratch-blocks,griffpatch/scratch-blocks,griffpatch/scratch-blocks,LLK/scratch-blocks,griffpatch/scratch-blocks,gengshenghong/scratch-blocks,gengshenghong/scratch-blocks