Hello,
as you know, using ctrl m while focused on a friend in your list of friends or in the online users list allows you to type your private message. With the latest update of Skype, version 8.60, Skype has added support for global hotkeys. The reason this is important is because ctrl M in Skype is used to mute your microphone, so while in a call it is impossible to use this Playroom shortcut.
Would it be possible that in addition to Ctrl m, Shift plus m on a friend does the same thing? In most programs that support global hotkeys, it is possible to customize them, however in Skype this is currently not possible and thus my reason for suggesting it to the Playroom instead to introduce one alternative shortcut.
Thanks for your consideration.

good idea

It would kind of interfere with first-letter navigation wouldn't it.

Why? To navigate by the first letter you would just press M. All friends in the list are lowercase anyway, so whether you use shift or not doesn't make a difference.

What do I know. Shift+M did work though. I wouldn't know if there is a way to make that particular shortcut do something else instead since I'm not a programmer. I hope it does for the sake of implementing that feature.