I think it would be a good idea to be able to repeat a line entered in the input field. Like on mirc which has a buffer where i can scroll thru the last inputs i made. It a nice feature if one enters a command and its not beeing executed because of an error. You just hit the arrow up key and it shows up again so one can correct and resend it. I think a buffer of the last 10 Lines would be enough. This buffer should be handled by the client.
Greetings
Thomas