I think it is a nicely thought out idea, but i do see one issue. you could end up accidentally inviting someone that you don't want in the party. so there should be a "confirm" button in place if this were to get added.
- An issue might be accidently inviting friends while you actually wanted to chat with them by misclicking.
- One solution would be to only let the right-click feature paste the command in the chat, like with /fmsg. This would also further help prevent spamming.
- Another solution would be the introduction of the '/p list' command, a command that lists all online friends. These friends could then on-click be invited to your party much like you can message your friends with the '/f list' command.