This might be considered a feature request. I think
when I'm in a channel and press #<tab> it should tab to
the current channel but it doesn't. So I type the first
letter or couple of letters and press <tab>.
Sometimes I might be in two channels where those
letters match both channels, e.g. #chat and #chatzone.
If I wanted to do something like use CTCP on #chatzone
I would out of habit type /ctcp #cha<tab> FINGER
without checking to see if it had tabbed to the wrong
channel when in fact it tabbed to #chat. I think it's
common sense that if two channels match a <tab> or # is
used on its own it should default to the current channel.