Autocomplete is not working

Since I've been using pgAdmin 1.8.0 auto complete on OS X is simply not working.

I can get a pop-up window to show (using ctrl+space) and it lists the
tables. I can only move the selection down one place however where it
selects both the first and second rows. Any further attempts to select
a table below the top two, do nothing.

Here is a link to a screenshot of the problem:
http://img509.imageshack.us/img509/2240/screenshotyd2.jpg

I can select a table from the popup using the mouse however.

I'm using pgAdmin 1.8.0 Beta 5 (rev: 6630:6631) on Mac OS X 10.4.10.

Thanks for the great product BTW, it's nice and quick blitzing anything else :)