This have just been a bit confusing for me, but I'll try to be as precise as I can.
Right, first of all, I don't get any steam invite prompts when I enter tier 1 lobbies. I've checked and double-checked to make sure that the prompt is enabled in my settings before logging in with my steam account, but I still can't seem to make it appear. I've looked online (read: googled) for some information in regards to steam invites, but I haven't been able to find any concrete information whatsoever. So, if anyone could answer the following questions, it would be very appreciated.
1. Does my steam friends need to be logged into steam or even logged into Spiral Knights for the prompt to appear?
2. Does my steam friends have to have Spiral Knights installed for me to invite them?
3. Do I have to have my steam friends in my friends list on Spiral Knights in order to invite them?
Any answers would be much obliged. I am trying to get that steam mask thing. :)
From my experience, your steam friends need to be online for you to be able to send invites out. When I do a certain tier 1 run, the list always changes as to who I can invite because people are on and off through out the day.
It should be popping up for you. As to why it's not, I can not answer.