Im not sure if that works. I took a look at the discussion and saw it started 7 months ago. Right now my impression is that mattermost lacks a lot basic things and nothing is done about it or at least very slowly. I think the whole development process is somehow not optimal. I rarely see a project that is so popular but makes this little progress.
We are currently evaluating mattermost for our company but come across many problems. For example if someone pastes an image from clipboard, others cannot view it in original size expect they download and save it. I'm going to create a bug or feature request for that but this is something so basic it should have been included from the beginning. This is just an example. There are many more "small" issues like this.