This doesn't seem to be a qtmir issue. I think the problem lies in a regression in the Mir socket connections. Connections for sessions created by mir_prompt_session_new_fds_for_prompt_providers aren't passing the correct client pid to the sessions.
So mir cannot find the session to overlay the child on top of.
This doesn't seem to be a qtmir issue. I think the problem lies in a regression in the Mir socket connections. Connections for sessions created by mir_prompt_ session_ new_fds_ for_prompt_ providers aren't passing the correct client pid to the sessions.
So mir cannot find the session to overlay the child on top of.