Auto-completion is available in Beta 1.0, and works the same way as in Alpha 0.9.9 (Ctrl+Space combination). "Automatically show completion panel" is a different option, and it's not yet implemented properly.
Thanks! I just downloaded it again and both features worked perfectly.
I just had a little issue... I downloaded the Beta 1 version, but the "Automatically show completion panel" option is disabled so I can't use the auto-completion feature. I had to downgrade to Alpha 0.9.9 to have the auto-completion, but now I don't have the syntax highlighting enabled (which I don't really need that much... but it would be great to have them both :P).