Feature summary (what you would like to be able to do and where):
See, for example, https://ru.m.wikipedia.org/wiki/Обсуждение_участника:Da1da1500
Benefits (why should this be implemented?):
By default, DiscussionTools collapses all sections no matter how many of them are on the page. I propose a small feature: to special-case not collapsing the section (or opening by default?) if there is only one present, since that would make a better experience for mobile users in cases where, for example, welcome messages are posted on their talk pages, requiring less action from them to read them.