Delphi 2009 has a lag of about 2 seconds after typing "." (dot) symbol on a 3 Ghz Core Duo iMac machine. Previously on Delphi 2007 the lag was about 1 second. What happened?
And most importantly please allow to type characters after the dot is typed and Code Insight is evaluating, currently it it eating the symbols you are typing during the Code Insight is being displayed.
It is very annoying. It hasn't been like that since Delphi 5 for sure. I guess you changed something in Delphi 2009.
It got way better with Andreas Hausladen's IDE Fix Pack 4: http://andy.jgknet.de/blog/2010/11/the-idefixpack-4-0-beta-begins/