Please upgrade here. These earlier versions are no longer being updated and have security issues.
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What is the plugin to use here?

Which plugins use this forum?
To write the text ... which plugin?
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Comments
a proprietary version of buttonbar.
your version of buttonbar plugin may look slightly different but is the closest thing right now.
http://vanillaforums.org/discussion/19021/what-plugins-are-used-here-on-the-vanilla-forums-community
http://vanillaforums.org/discussion/comment/202489#Comment_202489
if it doesn't show up in your dashboard as an available plugin already - it is here ....
if you already have it in your dashboard, no need to download.
http://vanillaforums.org/addon/buttonbar-plugin
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.