Thank you for reporting the issue to us.
We have fixed the issue in the latest version of InDesign, Id 15.0
Please upgrade your InDesign application to the latest version to try out the fix.
If you face any problems with the new update, do let us know in the comments.
You may also follow the below given link for the list of all fixed issues in Id 15.0
-InDesign TeamAnonymous commented
縦書きでもスムーズに下線機能が使えるよう、ぜひ修正をよろしくお願いいたします。Anonymous supported this idea ·