The last item in the gear menu when you write a reply is very difficult to access, because it is hidden behind the keyboard. (Well, I don’t need “Mermaid” that often, but I know a forum where “spoiler” is the last one.)
When you start a new topic, collapsing the keyboard works to access everything. However, for replies, collapsing the keyboard does not help because then the whole block is placed at the bottom.
The only workaround I found is to collapse the keyboard before clicking the gear.