Index -> Interface -> User Lists

To the right of the chat window in each lobby is a list of the users currently in that lobby. Next to each player's name is his Player Avatar. The color of a name indicates that user's status.

• White indicates the player is currently in the lobby.
• Green indicates the player is in the process of starting a game.
• Red indicates the player is in a game, the Deck Builder, or the Collection Manager.
• Dark Gray indicates the player is at the Main Lobby.

If you right-click on a player's name or icon, you'll get a dropdown list with several useful commands:

• Challenge (only available in the Casual Games Lobby)
• Join hosted game (only available in the Casual Games Lobby)
• Observe match (only available in the Casual Games Lobby)
• Trade (only available in the Trade Lobby)
• Add to friends list
• Ignore
• Invite to guild
• Kick from guild
• Get Info