Windows terminal servers (e.g. multiple users logged into one machine) is supported, there are a few limitations:

If there are many users syncing files, we only have one sync queue. Meaning all users will share a unified sync queue. Therefore, if you add a file, it will wait for the existing sync actions to be completed before sending other files up.
Only one agent gui will receive notifications. The other agent gui(s) may appear to be offline or disconnected, but syncing will work.