Today, I discovered in the latest announcement from JRO that the official has modified the height of the 'select' bar to accommodate a maximum of 15 options.
Can we also make modifications?
Here is the link: https://ragnarokonline.gungho.jp/news/play/jf0lnt0000001jfi.html
and "■NPCとの会話中に表示される選択肢が、最大15個まで上下のスクロールなしで表示されるように機能を拡張いたしました。"
means "■We have expanded the functionality to display choices during conversations with NPCs without the need for vertical scrolling, allowing for a maximum of 15 options."