Allow adding more users to create a conference call from the call itself
Issue generated from Tuleap's migration script. Originally submitted by: Ciro Santilli (cirosantilli)
To make a conference call, you have to drag drop one ongoing call into another as shown at: https://www.youtube.com/watch?v=xAyIHhbQt3A&t=483
This is too hard to guess for some users (e.g. me).
Instead, there should be a button on the call screen (that shows the video) "Add more users to call".
Alternatively, when you right click on an item of the Conversation tab with an an ongoing call, there could be an item: "Add more users to call"