As a room owner, you can move messages to another chat room. When you do that, a box where you can search for a suitable target room is displayed.
(In more detail, when you select "move messages" from the "room" dropdown, you first select the messages you want to move, then click "relocate" to proceed to select a room. You are now in the "Move posts" pseudo-dialog.)
The problem with this is that by default (at least in Chrome) there is nothing useful you can do until you first click in the text box in this dialog.
This is a minor annoyance, but also a glaring usability bug which should be easy to fix. When this dialog comes up, the text box should already be selected, so that you can type the name of the target room without first clicking there.