study: only set chapter draggable class if applicable
study: only set chapter draggable class if applicable

arex1337/lila,arex1337/lila,luanlv/lila,luanlv/lila,arex1337/lila,luanlv/lila,arex1337/lila,luanlv/lila,arex1337/lila,arex1337/lila,arex1337/lila,luanlv/lila,luanlv/lila,luanlv/lila