I'm not sure if it's been brought up before, but could a means of inviting new participants to PMs be added? This doesn't seem to be possible currently (though I'm relatively new here, so I may simply be missing something obvious).

In the same vein, it would also be nice if there was a feature to remove oneself from an ongoing PM thread, as well as for the OP of a PM thread to have the ability to remove participants if needed/desired.

Apologies in advance if I'm asking questions that have already been answered elsewhere, or reporting "bugs" that are there by design or that have already been fixed.